THE SINISTER SIGNPOST

Racing cars! Mystery! Adventure! These elements combine to give Frank and Joe Hardy one of the most dangerous and intriguing cases of their careers.

It all starts when their father, Fenton Hardy, is engaged by an experimental race car and motor designer to investigate a series of mysterious accidents. Three of his drivers have crashed because the windshields of their cars were suddenly crazed, thus cutting off forward vision. Frank and Joe uncover one slim clue. Each of the drivers had seen a signpost marked DANGER shortly before his accident. The young detectives investigate, only to discover that the signposts have vanished. What happened to them? And what sinister purpose did they server

The attempted theft of a secret experimental motor and the kidnapping of a famous race horse are part of this thrilling case, which proves to be as sinister as the signposts themselves.

The Hardysâ€™ escape took the men completely by surprise

Copyright Â© 1996, 1968, 1936 by Simon & Schuster, Inc. All rights reserved.

Published by Grosset & Dunlap, Inc., a member of The Putnam &
Grosset Group, New York. Published simultaneously in Canada. S.A.
THE HARDY BOYSÂ® is a registered trademark of Simon & Schuster, Inc.
GROSSET & DUNLAP is a trademark of Grosset & Dunlap, Inc.

eISBN : 978-1-101-07629-3

2008 Printing

http://us.penguingroup.com

CHAPTER I

Danger on Wheels

âDo you see what I see?â Joe Hardy asked his brother.

âItâs a dragster,â Frank replied. âTheyâre not supposed to be driven on public roads. At least not in this state.â

The Hardys were driving home from Taylorville along Shore Road in their open convertible. It was a sunny summer afternoon. So far, they had encountered almost no traffic. Now Frank was gaining on the slow-moving, bright-orange racing car. In the driverâs seat, situated aft of the carâs massive rear wheels, sat a helmeted, black-jacketed figure.

âHeâs sure traveling at low speed,â Joe remarked. âI wonder why.â

Frank, dark-haired and eighteen, stepped on the gas and attempted to pass the other vehicle. The driver of the dragster increased his own speed and prevented the convertible from going by.

âWhatâs he trying to do? Cause an accident?â Joe said angrily.

Frank was forced to return to his position behind the dragster. As he did, the driver again reduced speed to a snailâs pace.

Blond-haired Joe, who was a year younger and more impetuous than Frank, stood up and cupped his hands over his mouth. âOkay!â he shouted at the other driver. âYouâve had your fun! Now let us by!â

Frank made another attempt to pass. Suddenly the driver of the dragster maneuvered his vehicle in such a way that its left rear wheel slammed up against the right front wheel of the Hardysâ car.

âWeâre out of control!â Joe yelled.

Their car swerved violently as a result of the impact. Frank struggled with the steering wheel and managed to regain control. He quickly came to a stop. The boys watched as the dragster sped down the road out of sight.

âIâd like to get my hands on that clown!â Joe said, fuming.

âSo would I,â Frank agreed. âBut the dragster had no license plates. Weâd have a hard time trying to track down the car.â

The boys inspected the damage to their convertible. The right front fender was crumpled and the rim of the wheel badly bent.

âWeâd better replace the wheel with our spare,â Frank suggested.

The Hardys jacked up the car. While they worked, a large, open-panel truck approached on the opposite side of the road. As it flashed by, Joe caught a glimpse of a bright-orange dragster in the rear of the vehicle.

âLook!â he exclaimed. âThat must be the same race car that rammed us!â

Frank jumped to his feet and peered in the direction his brother was pointing. By now the speeding truck had vanished around a bend in the road.

âEverything happened so fast,â Joe said disappointedly, âI wasnât able to get the license number of the truck.â

âToo bad,â Frank commented. âItâll be miles away by the time we finish putting on the spare.â

When the job was completed, the boys continued their journey home. Mrs. Hardy, a slim, graceful woman, greeted them when they arrived.

âIâm so glad youâre back,â she announced. âYour father wants to see you right away.â

The boys sprinted up the stairs to their fatherâs study on the second floor. Mr. Hardy, a distinguished-looking, middle-aged man, was seated behind his desk.

âHi, Dad!â Joe greeted him. âMother said you wanted to see us.â

âHello, boys,â he replied. âI just accepted a new case that Iâd like to discuss with you two.â

Frank and Joe glanced at each other excitedly. Then they took seats near Mr. Hardyâs desk. He sat quietly for a moment, studying a myriad of notes he had spread out in front of him.

Fenton Hardy was an extremely meticulous man. Formerly a member of the New York City Police Department, he now worked as a private detective. His exceptional skill in solving baffling crimes had made him famous. In fact, many of his methods were studied and adopted by law-enforcement agencies throughout the world. Frank and Joe had inherited their fatherâs talent, and often assisted him with his cases.

âYes,â Mr. Hardy said finally as he glanced up from his notes. âI believe weâre in for a challenging case.â

âWe?â Joe exclaimed. âDid you sayâwe?â

Their father smiled. Although in his mid-forties, he appeared much younger than his years. âThatâs right,â he assured his sons. âIâm going to need your help.â

âThatâs great!â Frank declared. âWhat kind of case is it?â

Mr. Hardy leaned back in his chair. âHave you ever heard of the Alden Automotive Research and Development Company?â

âYes,â Joe answered quickly. âItâs a firm just a few miles south of Clayton. I believe they experiment with high-speed cars.â

âCorrect,â the detective replied. âThe company makes components for regular stock automobiles as well. Alsoââ

âIsnât Keith Alden the president of the company?â Frank interrupted. âI remember reading about him in the newspapers. He was once a famous racing driver.â

âThatâs right,â Mr. Hardy replied.

He went on to tell his sons Alden had designed an experimental turbine motor for his high-speed race cars.

âThe power plant is so revolutionary that the government has shown an interest in it. However,â the detective continued, âdespite his efforts to keep the motor a secret, Mr. Alden suspects that someone has learned about it and is trying to steal the plans.â

âDoes he have any idea who the person is?â Joe asked.

âNone,â his father replied. âAnd hereâs something else. Two of his cars, in which the motor was installed, met with accidents of a very mysterious nature.â

Mr. Hardy stated that Alden wanted to put his motor and car designs to a real test by entering them in road race competitions. âIt was during test runs that the vehicles were totally destroyed. The drivers barely escaped with their lives.â

âWhat happened?â Joe asked.

âThe windshields of the cars suddenly crazed,â he said, âand cut off the driversâ forward vision. As a result, they went out of control and crashed.â

âWindshields crazed?â Joe muttered.

âYes,â Mr. Hardy answered. âThey turned almost a milky white.â

âBut how could that happen?â Frank asked.

âWe donât know,â his father admitted. âAt first, Alden thought the windshields might have been made of a faulty material. But after a laboratory test, that theory proved to be wrong.â

âWhatâs Frankâs and my assignment?â Joe questioned eagerly.

Mr. Hardy rose from his chair and slowly paced the floor. âIâm going to run a check on all of Aldenâs employees,â he said. âThatâs just a matter of getting hold of the personnel files at the plant. However, such information seldom reveals the whole story about a man. Iâd like to place as many of the workers as possible under close observation, especially the men in the research department.â

âAnd you want Joe and me for an undercover job!â Frank exclaimed.

Their father grinned. âYouâre way ahead of me,â he replied. âBut youâre right. Itâs exactly what I have in mind.â

âThat means weâll have to act as employees ourselves,â Frank said. âThe problem is how can we do it without arousing suspicion?â

âI have an idea,â his brother answered. âBayport High introduced a basic automotive engineering course last term. Suppose we say we want to work at the plant to get some practical experience.â

âThatâs it,â Frank said. âAnd the timing is perfect, since our school vacations have just started.â

âSounds good,â Mr. Hardy agreed. âYouâll have a chance to meet Mr. Alden tomorrow. Heâs permitting an automobile club to use his private race track for a dragster and a stock-car competition. Weâre invited to be his guests.â

âGreat!â Joe exclaimed. âWould it be all right to ask Chet to come along?â

âI donât see why not,â his father replied.

Chet Morton was a school chum of the Hardys. He was a plump, good-natured boy, who lived with his family on a farm near Bayport.

Just then Mrs. Hardy announced that supper was ready. The boys and their father were about to leave the study when an object crashed through one of the windows. It landed in a corner of the room.

âGet down!â Frank yelled.

A split second later there was a muffled explosion!

CHAPTER II

Threats

INSTANTLY the room was filled with thick, boiling clouds of smoke.

âWhat happened?â Joe shouted.

âIt must have been a bomb!â Frank cried out.

The Hardys held their breaths and groped their way through the choking smoke. There was no sign of fire. Frank, Joe, and their father soaked handkerchiefs with water, held them over their faces, then began flinging open all the windows on the second floor. Gradually the smoke cleared.

âEek!â they heard a woman scream. The boys turned to see the tall, angular form of their Aunt Gertrude rushing up the stairs, followed closely by Mrs. Hardy.

âEverythingâs all right!â Frank announced, in an effort to calm the women.

âSmoke!â Aunt Gertrude cried. âCall the fire department! Call the police! Do something!â

âNo need to get excited,â Mr. Hardy said. âThereâs no fire. Please go back downstairs. Weâll explain everything later.â

The boys dashed from the house to look for the thrower of the smoke bomb. Not finding him, the young detectives searched in a widening circle. Presently Frank noticed a small glittering object some distance away. He ran to the spot and picked it up.

âTake a look at this!â he called to his brother.

âWhyâitâs a rifle cartridge case,â Joe said as he examined Frankâs discovery.

âLetâs show it to Dad.â

The boys returned to their fatherâs study. Mr. Hardy was examining fragments of the bomb. He held up a metal tube about a foot long. âThis is all thatâs left of what Iâm certain was a rifle grenade.â

Frankâs eyes widened with astonishment. âA rifle grenade?â he echoed.

âYes,â Mr. Hardy replied. âThe explosive section is attached to one end of this tube. The other end fits over the muzzle of a rifle. Itâs then fired from the weapon by means of a blank cartridge shell.â

âA shell like this?â Frank said, handing his father the cartridge case he had picked up.

An expression of surprise spread across the older detectiveâs face. âExactly!â he declared, studying the small object. âWhere did you find this?â

âJust a few yards beyond our own grounds,â Frank said. âThat explains why we saw no footprints on our property.â

Mr. Hardy handed his sons a fragment of paper. âThis was tied to the shaft of the smoke grenade,â he told them.

Frank and Joe were amazed to find that it was a handwritten message which read:

You are being watched. Drop the Alden case, or the next smoke will be lethal!

âLeaping lizards!â Joe exclaimed. âWe havenât even started on the case yet, and already weâre being threatened!â

âThis is something we canât ignore,â Mr. Hardy said. âWeâll have to be extra cautious. And as for your mother and aunt, Iâm going to ask them to take a little trip. We canât risk leaving them alone in the house.â

During supper the two women rebuked the boysâ father for suggesting that they go away.

âWould a sea captain be the first to leave his sinking ship?â Aunt Gertrude exclaimed. âNot on your life! I, for one, will not budge from this house!â

Mr. Hardyâs sister, unmarried, had a peppery temperament. She was always quick to express her opinions openly, and often made dire predictions about the horrible fate awaiting all detectives.

âWe know youâre concerned for our safety,â Mrs. Hardy added in her soft-spoken voice. âBut we will not leave here.â

âWellâall right,â her husband conceded reluctantly. âHowever, Iâm going to call Chief Collig at headquarters and request that a couple of guards be posted near the house day and night.â

The next day, Saturday, Mr. Hardy and the boys had an early breakfast. Then, after driving to the Morton farm to pick up Chet, they headed for Aldenâs private race track near Clayton.

âI canât wait to see the stock-car competitions,â Chet said as he peeled a large banana. âIn fact, Iâve been thinking of getting into the sport myself. Thereâs an old car in my fatherâs barn Iâm planning to fix up.â

âOh-oh,â Joe remarked jokingly. âThatâs one hobby you had better stay away from.â

âDonât worry,â Frank added with a laugh. âChetâs car will end up as a diner on wheels, rather than a threat to the racing world.â

âCut the small talk,â their friend retorted. âYou two masterminds are jealous because Iâm the daredevil type. Weâre a species that eat more because we need tons of energy.â

The Hardys and Chet arrived at the track in less than an hour. The area was a beehive of activity. Bright-colored stock cars and dragsters gleamed in the sun as drivers prepared their vehicles for the dayâs competitions.

âYou fellows enjoy yourselves looking at some of these cars,â Mr. Hardy said. âIâll locate Mr. Alden and bring him back here.â

âOkay, Dad.â

The boys began to stroll around the area. Suddenly Joe grabbed his brotherâs arm and exclaimed, âThereâs the dragster that rammed us!â

âIt sure looks like it,â Frank agreed. âSame color. But letâs not jump to conclusions. Weâll ask the driver some questions first.â

The Hardys and Chet walked toward the dragster. A slim, sandy-haired young man was working on the engine of the car.

âAre you the owner of this dragster?â Frank queried.

âYeah,â the young man sneered. âWhatâs it to you?â

âNow hold on!â Joe interjected. âNo need to get hot about it. He just asked a simple question.â

âWere you driving along Shore Road in Bayport yesterday?â Frank continued.

The drag-strip racer hesitated a moment. âWhy donât you guys take a walk?â he shot back finally. âEspecially the fat one with you. He looks like he could use some exercise.â

âWhy donât you take a walk?â the young man snarled

âWho do you think youâre talking to?â Chet snapped.

âJust a second,â Joe said. He ran his hand around the outer surface of the vehicleâs left rear wheel. âThe wall of this tire is roughed up. It must have rubbed hard against something.â

âSuch as our car!â Frank stated.

âGet away from that wheel!â the young man growled.

He gave Joe a shove that sent the boy crashing to the ground. Like a flash Joe was up on his feet. He rushed at his attacker and pinned his opponentâs arms behind his back in a jujitsu maneuver.

âLet me go!â the young man cried.

At that moment Mr. Hardy appeared with Keith Alden. He was a tall, slim man with patrician features. His dark hair was slightly gray at the temples.

Mr. Alden looked troubled âWhatâs going on here?â he demanded.

âAre you boys having trouble?â Mr. Hardy asked quickly.

The car manufacturer spoke to Joe in a displeased voice. âWhy are you holding onto my son like that?â

âYourâyour son?â Frank stammered.

Joe released his grip on the young man.

âYes,â Alden continued. âThis is my son Rogerâ

Mr. Hardy introduced his client to the boys. Except for Roger, everyone was mutually embarrassed.

âThese guys,â the young man shouted, âare trying to pin some sort of car accident on me!â

Alden eyed Roger suspiciously. âI donât think the Hardy boys would accuse anyone without good reason. If you were involved in an accident, it wouldnât be the first time.â

Frank and Joe glanced at each other. It seemed wise not to force the issue. They told Mr. Alden about their encounter with a dragster the previous day, but could not say for certain that the driver of the bright-orange car was Roger.

âThen only my son can clear up this matter,â Alden said. He put the question to Roger.

The young man became even more arrogant. âI didnât ram into anybodyâs car, and I never heard of Shore Road!â

His father was in a quandary. Finally he said, âUntil this matter can be investigated further, I forbid you to drive your dragster in the competitions today.â

âWeâll see about that!â Roger muttered defiantly. He glared at the Hardys, then turned and walked off at a furious pace.

âI donât know what to do about my son,â Alden said with remorse. âHis mother died several years ago, and I havenât been able to spend much time with him. Heâs been getting more difficult to live with every day.â

âIâm sure heâll straighten out,â Mr. Hardy remarked sympathetically.

âI hope so,â Alden replied. Suddenly his mood changed. He turned to Frank and Joe. âNow down to business. Your father tells me you two are going to work with him on the case,â he said.

âThatâs right,â Frank replied.

âExcellent! Iâm sure you have some questions of your own youâll want to ask me. However, I must fly to Washington immediately after the competitions. How about all of us meeting in my office Monday morning?â

The Hardys nodded.

Alden looked at his wrist watch. âIt is time for me to get to my post. Iâm the official timekeeper for the stock-car runs. Perhaps you would like to join me out on the track.â

âWould we!â the boys answered excitedly.

As they started to Walk off, Frank bent down and picked up a small packet which had fallen from his brotherâs pocket during the scuffle. It was Joeâs detective kit. Each of the Hardys carried one. Among the items that had spilled out was a magnifying glass and a metal signaling mirror. He handed the kit to Joe.

Suddenly a voice crackled from the loudspeaker of the P.A. system.

âThe first trial run will be made by car number twenty-two. The driver is Roger Alden!â

âWhat!â exploded Alden. âHow did he get his hands on a car? I must stop him! Roger doesnât have enough experience for closed-circuit racing!â

CHAPTER III

Prime Suspect

ALDEN rushed toward the starting line with the Hardys close at his heels.

âStop that car!â he shouted.

But it was too late. Roger roared off.

âFlag that car down!â Alden ordered one of the track officials.

âIâll try to signal him with my mirror when he comes along the straightaway,â Joe said.

Frank and Joe ran alongside the track opposite to the direction Roger was headed. They watched him as he skidded dangerously on the far turn.

âDid you see that?â Frank yelled.

âYes. He took that curve too fast.â

The boys hurried down the straightaway. As Roger came around the second far turn, his car spun out of control and crashed through the fence on the sideline. A huge geyser of dust erupted from the spot.

Frank and Joe rushed to the scene of the accident. An ambulance sped by them with its siren screaming. They arrived just as two white-coated men were helping Roger move away from the damaged vehicle.

âIs he hurt?â Joe asked quickly.

âNo,â one of the men replied. âHeâs lucky. I think he just had the wind knocked out of him. But weâll take him to the hospital for an examination, anyway.â

Shortly Rogerâs father and Mr. Hardy came running up.

âAre you all right?â Alden asked his son nervously.

âIâI guess so,â Roger gasped, still trying to catch his breath. Then he glared at the Hardys and pointed an accusing finger at them. âYou guys are the cause of this!â he screamed. âYou reflected sunlight into my eyes with that mirror of yours!â

âYouâre crazy!â Joe retorted.

A rangy young man appeared and gazed at the wrecked car in disbelief. âMy car!â he groaned. âItâs almost totally demolished!â

âAre you the owner?â Alden queried.

âYes, I am.â

âHow is it my son was driving your racer?â

âRoger offered me a hundred bucks if I would let him make the trial run,â the young man explained. âNow all I have is a pile of junk.â

âServes you right,â Alden snapped, âbut Iâll pay for the damage.â

Roger was helped into the ambulance and taken to the hospital. Although his father was greatly upset over the incident, he did not request that the competitions be discontinued. Instead, Alden told the participants to carry on. At the signal, engines began roaring to life. The Hardys and Chet watched the dayâs activities and were thrilled by the performance of the skillful drivers.

After dropping Chet off at the Morton farm, the three detectives headed home. When they arrived, Mrs. Hardy announced that supper was ready to be served. As they ate, the boys discussed the dayâs events.

Aunt Gertrude looked at them scornfully. âRacing of any kind is just dreadful! It should be outlawed!â

âWhen properly organized,â Frank put in, âitâs a fine sport.â

âI call it utter nonsense!â Aunt Gertrude retorted. She hurried out of the room before her nephews could argue the point.

The next day the boys rose late. After eating a hearty breakfast and attending church services, they settled down to read the voluminous Sunday newspapers. Shortly the telephone rang. Frank scooped up the receiver. The caller was Iola Morton, Chetâs sister.

âChet wonât be able to see you later,â she sobbed. âHeâs had an accident!â

Frank and Joe leaped into their convertible and drove to the Morton farm. They arrived to find the entire family standing on the front porch of the house. Chet was seated on the steps, exclaiming that he was all right. His face was blackened with soot.

âI donât need a doctor!â the chubby youth insisted.

âWhat happened?â Frank asked worriedly.

Mr. Morton, a good-looking, normally jolly man, turned to the Hardys. âChet was experimenting with a highly volatile fuel on the engine of that old car I keep in the barn. He was pouring some into the carburetor when it suddenly blew up.â

âIt seems the racing bug has bitten him,â said Iola, a slim, pretty girl. She was a witty, light-hearted person and was a school chum of the Hardys. Iola was Joeâs favorite date.

âI was afraid something like this would happen,â Frank remarked. âHowever, I didnât expect it so soon.â

Mrs. Morton, an attractive, dark-haired woman, hurried to meet Dr. Mills, a Bayport physician, as he drove up to the house. He examined Chet, then left after saying that fortunately the boy had not been injured.

âYouâd better call off your experiments,â Joe advised his friend.

âIâll make sure he does,â Mr. Morton said. âIâm getting rid of that old car right away.â

âBut you canât!â Chet protested. âIâm on the threshold of producing the Morton super-duty racing car!â

Frank and Joe helped to convince him that such experiments should be left to the experts. Chet was crestfallen for a moment, then his face suddenly brightened.

âIâll drop the race-car project in favor of another idea,â he said. âA rocket-propelled bicycle!â The Hardys shook their heads in despair and returned home.

Monday morning found Mr. Hardy and his sons in Keith Aldenâs office. The company president was seated comfortably behind his desk, ready to discuss the case with them.

Frank was the first to speak. âDad says that you suspect someone is trying to steal your experimental motor. Why?â

âMy motor,â Alden replied, âuses a valve of a very unusual design. In fact, weâre not equipped here at the plant to make one. However, I learned of a company on the West Coast that specializes in valve manufacturing. They said they could do the job, so I gave them the green light.â

He went on to say that one day Mr. Dillon, president of the valve company, had telephoned him excitedly. A stranger, who refused to identify himself, had appeared with the specifications of a valve exactly like the one to be used in Aldenâs experimental motor.

Keith Alden rubbed the back of his neck. âBeats me how the fellow got hold of my design.â

âWhatâs the name of the company, sir?â Joe asked.

âExeter Valve. It s a small outfit and, lucky for me, very reputable. Mr. Dillon told the guy heâd like to study the specifications further before agreeing to handle the job. The stranger refused and scooted off.â

âDid you get a description of him?â Frank asked.

âYes,â Alden replied. âHe was tall, wore black rimmed glasses, and had a beard and mustache that looked phony.â

âObviously a disguise,â Mr. Hardy commented.

âIâm certain it was by sheer accident that the stranger went to the same company I was dealing with,â Alden declared. âAnd Iâm also sure that his valve sketch was a direct copy of my own design.â

âLeaping lizards!â Joe interjected. âMaybe the stranger has the plans to your whole motor!â

âWe doubt that,â Mr. Hardy said.

Alden grinned. âYour father is referring to the precautions I have taken to prevent the plans from being stolen.â

âWhat kind of precautions?â Frank asked.

Alden explained that there were only two sets of plans in existence. âOne set, the original, is safely hidden. The other is recorded on film slides.

âThe work is divided among the technicians here,â the man continued. âNo one worker knows what the other is doing. Each receives his assignment in the form of a slide, which is placed in a burglarproof projector. He displays it on a small screen and uses it for his job.â

âSounds foolproof,â Joe commented.

âThatâs what I thought,â Alden said. âYet somehow specifications for my motor must be leaking out of the plant.â

âSo far,â Mr. Hardy told his sons, âonly half of the slides have ever been seen by anyone other than Mr. Alden. Thatâs why we doubt that the entire design has fallen into the wrong hands.â

The boys asked Alden if he had the slightest reason to suspect any of his workers.

âNo,â he replied. âAnd just to be sure, I had them all double-checked.â

âWhat about ex-employees?â Joe suggested. âHave you had any trouble in the past?â

Alden rubbed his chin dubiously. âCome to think of it, I did. But that was several months ago.â

He stated that Vilno Sigor, an engineer and designer, had worked in his research department. The man had created a number of small, but clever inventions which were used by the company.

âThen one day Vilno came to my office and accused me of picking his brain,â Alden said. âI told him that was what I was paying him for, and reminded him of the generous bonuses he received for his ideas. Vilno wanted more. He demanded a partnership in my firm. When I refused, he became furious and left. I havenât seen him since.â

âToo bad,â Frank muttered. âHe might have been our man.â

âNow take his twin brother Barto,â Alden remarked. âHeâs still employed in my research department as a sheet-metal worker. An excellent craftsman. His job is to fabricate the bodies of our experimental race cars.â

âA twin brother?â Frank exclaimed. âThatâs a lead. Barto could be in cahoots with Vilno!â

Alden grinned. âYouâd be wasting your time investigating him. Heâs the direct opposite of Vilno in engineering knowledge and in temperament. Even if he got a look at the plans of my motor, heâd never be able to understand them.â

Despite Aldenâs opinion of Barto, the boys were determined to list the sheet-metal worker as a prime suspect.

The young detectives asked about the two experimental cars that had met with accidents after their windshields had been mysteriously crazed. Alden told them that each of the vehicles was powered by a prototype of his motor.

âBut whether the accidents were the result of sabotage, I canât say,â he added.

Mr. Hardy spoke up. âRight now letâs tackle this case one step at a time,â he advised his sons. âWe have to assume that somewhere in this plant thereâs a clever crook. Heâs managing to steal specifications of the experimental motor. Our first job is to find out who he is. And weâll have to find him fast!â

CHAPTER IV

Fingerprint Hunt

âSo YOU want to work in my plant as undercover agents,â Alden said, when told about the boysâ plan. âI like the idea.â

âThanks,â Frank replied. âWhen do we start?â

âTomorrow, if thatâs all right with you fellows,â Alden said. He glanced at his wrist watch. âI see itâs nearly lunchtime. Letâs have some food.â

After a delicious meal in the companyâs cafeteria, Alden conducted the Hardys on a tour of the plant. The boys watched with interest as various machinists turned out parts for the experimental motor. Each of the men worked from a plan projected on a small screen.

The last item on the tour was a visit to the research department. There Alden introduced the boys and their father to Barto Sigor.

âI am pleased to meet you,â Barto said in a quiet voice. He was a short, stocky man with bushy eyebrows and dark, wavy hair. His steel-gray eyes were fixed on the young detectives.

âThese two lads will be working here in the plant for a while,â Alden told him. âTheyâre taking an automotive engineering course at school and would like to get a little practical experience.â

âAh,â Barto responded. âSo you want to learn the automobile business. Thatâs good. Do not hesitate to call on me if you have any questions.â

âWe wonât,â Joe answered.

Later, while driving home to Bayport, Frank and Joe discussed the case with their father.

Then Joe said, âWhatâs your opinion of Barto, Frank? He seems pleasant enough.â

âI agree heâs a weak suspect, butââ

âYou have something on your mind, son,â Mr. Hardy guessed. âWhat is it?â

âMr. Alden said that Barto would not understand the motor specifications even if he got a look at the plans,â Frank replied. âHowever, since Vilno and Barto are twins, itâs possible that they could have switched identities.â

âThereâs only one flaw in your theory,â Mr. Hardy said. âVilno is not a sheet-metal worker. How could he perform his brotherâs job at the plant?â

âI didnât think about that,â Frank admitted. âStill, Iâd like to check it out.â

âThereâs one way of settling the question,â the older detective suggested. âTry to get Bartoâs fingerprints. But do it without his knowledge. We donât want Barto, or anyone else in the plant, to suspect youâre working on a case.â

The boys retired early that night. The next morning they started for the Alden plant immediately after breakfast. Mr. Hardy, who had been supplied with a microfilm report of all the employeesâ records, remained at home to check the information against his files on criminals.

The boys spent the morning watching the skilled machinists perform their various tasks. Finally they positioned themselves so they could peer into the research department to observe Barto. The young detectives noticed that he wore a pair of thin rubber gloves constantly. Joe made a casual remark about this to another mechanic.

âBarto always keeps those gloves on,â the man said. âHe uses certain acids in his work. Also, he says the gloves give him a better grip on his tools.â

Eager to discuss the situation, the young detectives retreated to a secluded corner of the plant.

âThose gloves of Bartoâs make it impossible to get his fingerprints,â Joe commented.

âHeâll have to take them off sometime,â Frank pointed out. âMaybe when he has his lunch.â

At noon most of the workers went to the cafeteria. Barto, however, did not leave the shop. Instead, he walked to a clothes rack in one corner of the room and pulled a sandwich, wrapped in wax paper, from the pocket of his jacket. He then sat down on a bench, removed his gloves, and unwrapped the sandwich. The boys watched from a distance.

âWe might get a good print from that wax paper,â Joe whispered.

âRight,â his brother agreed. âLetâs see what he does with it.â

After Barto finished eating, he crumpled up the wax paper, put his gloves back on, and strolled out of the shop through an exit door. The young detectives rushed to a window and peered outside. There they spotted the suspect walking toward a flaming incinerator. The man tossed the wax paper into it and returned to the shop.

âWell, thatâs that,â Joe muttered disappointedly.

âWe canât waste too much time trying to get Bartoâs prints,â Frank said. âLetâs follow him when he quits work for the day.â

A few minutes before five oâclock the boys hurried to the parking lot to pick up their car. Then they posted themselves outside the main gate. Workers began to spill out of the plant.

âThereâs Barto!â Joe said.

The boys watched their suspect walk to a street corner and wait. Soon a bus came along and Barto climbed aboard. The boys followed the vehicle. Eventually the trail led them to the center of Clayton. The bus stopped and Barto got off.

âWeâll park the car and follow him on foot,â Frank declared.

They shadowed their suspect in the best detective fashion. Barto bought a newspaper. Then he stopped at a refreshment stand and ordered a glass of orange juice. When he had finished and walked off, Joe rushed to the stand to seize the glass. But before he could do so, a counter-man swept up the tumbler and plunged it into a sink filled with soapy water.

âOut of luck again,â Joe grumbled.

Finally Barto led the boys to a small, red-brick apartment house off the main street and entered the building. Frank and Joe waited a few minutes, then dashed into the lobby. They quickly checked the mailboxes and found that Barto lived in apartment 6B.

âWell, thereâs nothing more we can do today.â Frank sighed. âWe may as well go home. Maybe weâll come up with an idea before tomorrow.â

After supper the young detectives joined their father in his study.

âSorry to hear you havenât had any luck with your investigation today,â Mr. Hardy said. âNeither have I. So far, none of Aldenâs employees show up in my criminal files.â

âDid you check on Barto and his brother?â Frank queried.

âYes, I have.â

Mr. Hardy said that according to their records, the twins had been born in a small Midwest community. When they were still very young, their father had moved the family to Switzerland, where he accepted a job as an engineer. It was there that Vilno attended a university, and Barto had learned the sheet-metal trade.

âThe twins returned to the United States several years ago and started a business called Inventions, Incorporated,â Mr. Hardy continued. âThey didnât do very well and finally closed the shop. After that, it was a matter of job-hopping until they joined the Alden company.â

âHm! Not much to go on there,â Frank muttered. âHowever, I still want to follow through on the fingerprint angle.â

âMaybe we could get into Bartoâs apartment!â Joe suggested.

âWeâd need a court order to do that,â his brother said. âAt present we havenât any reason for justifying such a move.â

Frank thought for a moment, then suddenly sat bolt upright in his chair. âWait a minute! I have an idea!â he exclaimed. âBarto has to grab the doorknob to enter his apartment. I can hide in the hallway and wait until he comes home, then simply lift his prints from the knob.â

âSay! That might work!â Joe agreed.

âGo to it, boys. But be careful,â Mr. Hardy warned.

The hours dragged by slowly during the boysâ second day at the plant. At lunch they reviewed their plan. Frank would leave an hour before quitting time and take the bus to Clayton. Joe would drive their car and shadow Barto as they had done the previous day.

A few minutes before four oâclock Frank hurried from the plant and caught the bus to Clayton. Within half an hour he was climbing the stairs to the sixth floor where Bartoâs apartment was located. He found 6B, then stepped out through the exit door at the far end of the hallway. The young detective inched the door open so he could watch for his suspect.

âI hope Barto doesnât come home late tonight,â he thought.

While Frank waited, an elderly woman in work clothes appeared with a vacuum cleaner and a small trash disposal cart. She unlocked Bartoâs door and went inside. Shortly she reappeared with a wastebasket and dumped its contents into the cart. Then she went back into the apartment. The whirling sound of a vacuum cleaner could be heard.

âI wonder what was in the wastebasket,â Frank mused. âMaybe Iâll find a clue.â

He dashed to the cart and found several pieces of crumpled paper. Frank jammed them into his pocket and returned to his hiding place.

Eventually the cleaning woman emerged from the room, locked the door, and disappeared down the hallway with her paraphernalia. Frank ran to the door and wiped it clean so that Bartoâs prints would be the only ones present.

Half an hour passed. Then, from his hiding place, Frank spotted Barto walking down the hallway. The stocky man unlocked his door, twisted the knob, and went inside. When the door closed behind him, Frank sprang into action.

He dusted the knob with a fine, gray powder. Next, he took a strip of sticky tape from a celluloid container and carefully pressed it on the knob. A split second later he lifted off the tape, placed it back in the container, then rushed down the stairs and out of the building. He saw Joe in their car about a block away.

âWhew!â Frank said, out of breath. âI was afraid Barto was going to open his door any second.â

âMission accomplished?â his brother asked half-jokingly.

Frank held up the celluloid container. âHere are his fingerprints. Letâs take them to Chief Collig and have him check them right away.â

The boys drove directly to Bayport Police Headquarters. Chief Collig told them that he would send the data to the FBI by teletype and call the Hardys as soon as he received a reply.

Arriving home, the boys had a leisurely supper, then went to their crime lab located above the garage. There they examined the crumpled pieces of paper Frank had found in the disposal cart. All of them proved to be discarded advertising circulars, except one blank page.

âThis looks like the backing sheet for a typewritten letter,â Joe observed as he carefully flattened it out on a table.

âThen there must be word impressions on it,â his brother replied. âLetâs put it under the ultraviolet light.â

The boys treated the blank sheet with a chemical solution and placed it under a special lamp. Gradually, words began to show up clearly. The letter read:

6/2

Dear Eric:

Forgive me for taking so long to write you, but Iâve been so exhausted from work the last few days that I didnât feel I could write a coherent sentence. How I wish I had the stamina of two hard-working boys who have taken summer jobs at the plant. Any family would be proud to have sons like that.

As I already told you, my brother has left the Alden company. It came as a surprise to me because I did not detect anything in his behavior to lead me to believe he was dissatisfied with his job. I hope he manages to survive his own idiosyncracies. His reasons for leaving were extremely unreasonable, and I hope he eventually sees the error of his ways.

Because of my brother, I feel a bit embarrassed about continuing to work here. Iâm sure theyâre expecting me to leave also. I must admit I have been investigating other possible jobs, but now I realize it would be foolish of me to quit.

Hoping that luck will not continue to evade us, I am

Your friend,
Barto

The Hardys wondered to whom the letter had been sent, and if it might contain a coded message. After close examination, they concluded that the letter was quite ordinary. They kept it on file, nevertheless.

Later Chief Collig telephoned the boys. âI just got a reply on those prints you wanted checked,â he announced. âThey belong to a Barto Sigor.â

The news was shattering. The Hardys no longer had a prime suspect!

CHAPTER V

A Close Call

THE next day and a half at the plant proved disappointing for the boys. Despite their meticulous investigation, they failed to come up with a suspect.

âIâm ready to tackle this case from another angle,â Frank said. âWe may as well give up our undercover work here at the plant. Nothing more we can do.â

âWhat do you have in mind?â Joe asked.

âLooking into the accidents involving Aldenâs experimental race cars.â

âDo you think thereâs some connection between the accidents and the stealing of the motor specifications?â

Frank shrugged. âI donât know. Each of the cars was equipped with a prototype model of the motor. Yet why would anyone risk destroying the cars if thatâs what they were after?â

âLetâs have a talk with Alden,â Joe suggested.

In a little while the boys were seated in the presidentâs office.

âSo you want to investigate the accidents,â Alden said. âThatâs okay with me.â

âWeâd like to have a talk with the drivers,â Frank replied.

âYouâll find them in the garage opposite the research department,â Alden told them. âTheyâre getting another of my cars ready for a road race competition thatâs coming up. Their names are Jim Markus and Speed Johnston.â

Frank and Joe made their way toward a large, metal-covered building. Inside, a crew of mechanics was busy working on a bright-red experimental race car. Two wiry young men, in their mid-twenties, were watching the proceedings. They turned when the boys called out the names of the drivers.

âIâm Jim Markus,â one of them said.

âAnd my nameâs Speed Johnston,â announced the other, extending his hand in greeting. âWhat can we do for you?â

Frank and Joe questioned the drivers about their accidents. They told the Hardys that Alden had entered the experimental vehicles in the competitions in order to match their performance against other makes of cars. The explanation of the accidents were the same as Alden had given, except for a couple of interesting facts. First, each of the drivers had experienced a crazing of the windshield immediately after turning a sharp bend in the road. Shortly before it happened, each of them recalled seeing a sign marked DANGER.

âWould you show us on a map where the accidents took place?â Frank asked.

âSure thing,â Johnston replied.

He took out a road map and spread it on the floor. âMine happened here,â he said, jabbing a finger at the spot along a winding red line.

Markus stooped beside his companion. âAnd my accident took place right here,â he added, marking the location with a pencil.

The boys thanked the drivers for their help, then left, taking the map with them.

âThe road isnât far from here,â Frank commented. âJoe, letâs drive there and take a look around.â

Half an hour later the Hardys were guiding their convertible along a narrow, winding road. They arrived at the sharply curved segment indicated by Johnston and stopped.

âThis is the spot,â Frank remarked. âBut I donât see a sign marked DANGER.â

The boys got out and walked along the shoulder of the road.

âLook!â Joe exclaimed, pointing down at the ground. âThereâs a little mound of dirt. Someone has filled in a small hole.â

âYouâre right,â his brother agreed. âThatâs where the sign must have been. But why was it taken away?â

Puzzled, the boys returned to their car and drove on to the spot where Markus had said he had his accident. It proved to be another sharply curved segment on the road. The Hardys again examined the shoulder and found a similar mound of dirt.

âStrange,â Frank muttered. âI think weâre on to something. The only problem isâwhat?â

It was getting late, so the boys decided to drive home. When they arrived, Mrs. Hardy rushed out of the house to meet them.

âSomething has happened to your Aunt Gertrude!â she cried out.

âWhere is she?â Frank asked.

âIn the living room!â

The boys quickly followed their mother inside. There they found Aunt Gertrude slumped in a chair. Mrs. Hardy had placed a wet towel on her forehead.

âWhatâs wrong, Aunt Gertrude?â Frank asked.

Miss Hardy suddenly came to life. âThe telegram I just received!â she moaned. âWhat a dreadful inheritance! Read it!â

The boys looked down and saw the telegram on the floor beside her chair. Joe picked it up and they read the message. Both tried hard not to laugh.

âWhat a dreadful inheritance!â Aunt Gertrude moaned

âSo thatâs what this is all about,â Frank said finally. âYouâve inherited a stable of race horses.â

âA stable of retired race horses, you mean!â she exclaimed. âTheyâre the worst kind. Theyâve already fleeced the public!â

Mrs. Hardy smiled. âI think itâs wonderful,â she commented. âYou might get to like horses. They seem to grow on you in time.â

âLaura! How can you say such a thing!â Aunt Gertrude rebuked her. She slumped back in her chair. âAnd to think that this was wished on me by an old friend I forgot even existed. She apparently has no heirs.â

âWhere is the stable located?â Joe queried.

âIn Baltimore,â his aunt replied. âEven that is too close for me.â

âWhat do you plan to do with it?â Frank asked.

âSell the place!â Aunt Gertrude shot back. âAnd the quicker the better!â

âNow calm down,â Mrs. Hardy urged. âTomorrow weâll telephone the attorney handling the estate and see what this is all about.â

Aunt Gertrude remained silent all through supper. Finally a teasing cry of âGiddap!â from Joe sent her storming out of the room.

The next morning the boys went straight to Aldenâs office. They told him about the signs the drivers had mentioned and of their own investigation.

âSounds mysterious,â Alden remarked. âBut what harm could a sign do?â

âI canât answer that at the moment,â Frank admitted. âBut Iâve a hunch it has something to do with the accidents.â

Alden eyed the boys with interest. âHow do you plan to follow up your hunch?â

âThe last time we talked,â Frank recalled, âyou said that another of your experimental cars was being readied for a road race competition.â

âThatâs right. In fact, the race is scheduled for tomorrow.â

âWhere is it to take place?â Frank asked.

âOn a road not far from the one where the accidents happened. Why?â Alden asked.

âIf youâll point out the road for us on a map,â Frank explained, âJoe and I will travel the route shortly before the race starts. Maybe weâll spot one of ose signs. At least itâs worth a try.â

Alden pulled a map from his desk drawer and indicated the road to be used for the competition. Then the boys returned home and discussed the plan with their father.

âYou might be on to something,â Mr. Hardy said. âIâll drive the route with you.â

âThanks, Dad,â Frank replied. âBut we werenât going to use the car.â

âYouâre not planning to walk all the way?â the detective asked with a look of astonishment. âThe race will be over a course of several miles.â

âWe discussed it on the way home, Dad,â Joe put in. âWe plan to use our old bicycles. Theyâre still stored in the garage.â

Mr. Hardy leaned back in his chair and grinned. âI get it. Bicycles are noiseless. And if there is anything behind this sign theory of yours, you wonât scare off whoeverâs setting them up.â

âExactly,â Frank replied.

Before retiring for the night, the boys went to the garage and inspected their bicycles.

âThe tires have to be inflated, and a few drops of oil are needed here and there,â Joe observed. âOtherwise, theyâre in good shape.â

It took only a few minutes to do the job, then they rode their bicycles once around the block for a quick test run.

âLetâs load the bikes in our car,â Frank suggested, âso weâll be all set to go first thing in the morning.â

Frank and Joe got an early start. Mr. Hardy accompanied them to the starting line. There were about twenty stock cars lined up for the race. Each was painted in a different color scheme. Drivers and mechanics were milling around, waiting for the contest to begin. Alden was there and greeted the Hardys.

âHow much time do we have before the race gets under way?â Frank asked him.

âAbout thirty minutes. My car will be the first one off. Johnston is the driver.â

âThen weâd better get going right away,â Frank declared.

âBe careful,â Mr. Hardy urged.

The young detectives lifted their bicycles from the trunk, then pedaled down the road.

After they had covered most of the route, Joe sighed. âIâd forgotten how slow bicycling can be.â

âKeep going,â his brother said. âThe race will be starting any second now, and it wonât take the cars long to travel this far. We should cover as much of the route as we can before they do.â

As the boys continued, they noticed that the road was becoming treacherous for racing. It was flanked on one side by a rocky wall, and on the other by a sloping embankment with a drop of nearly a hundred feet.

Eventually Frank and Joe came to a sharp bend in the road. As they rounded it, Frank suddenly locked his brakes. Joe did the same. Just ahead was a large sign marked DANGER!

âLeaping lizards!â Joe declared in a hushed voice.

âThat sign is exactly like the ones Johnston and Markus described to us,â Frank observed. âLetâs take a look at it.â

âMaybe weâre being watched.â

âThatâs a chance weâll have to take.â

The boys laid their bicycles on the embankment and began walking toward the sign. When they reached it, they stopped and gazed at its face.

âWhat do you make of it?â Joe queried.

âSeems quite ordinary, except for one thing,â Frank answered. âItâs much thicker than most signs.â

At that instant the young detectives heard a faint, whirring noise.

âWhatâs that?â Joe said.

Frank listened. âIâd say itâs a generator of some kind,â he concluded.

âItâs coming from a spot a little farther down the road.â

The boys began to inch their way toward the source of the sound. Suddenly the roar of a motor became distinct. Each second it grew louder.

âThe first of the race cars is coming!â Joe exclaimed.

The Hardys turned just in time to see Aldenâs entry tearing around the sharp curve in the road. Suddenly it began to swerve out of control. The vehicle bounced into the air and hurtled directly toward the boys!

CHAPTER VI

Final Warning

THE racing car plunged toward Frank and Joe like some horrible monster eager to crush its prey. In a desperate move the boys leaped down the embankment and went tumbling head over heels to the bottom. They lay stunned. The next thing they knew, Mr. Hardy and Alden were leaning over them.

âAre you all right?â their father asked anxiously.

âIâmâIâm okay,â Frank assured him.

âMe too,â Joe added, rubbing his head gingerly.

âOne of the other drivers saw that there had been an accident and reported it,â Alden said. âWe got here just as fast as we could.â

Frank sprang to his feet. âYour driver Johnston! How is he?â

âFine, except for a few bruises,â Alden replied. He grinned. âI build very strong cars. My drivers are well-protected.â

The boys told the two men what they had seen.

âAnd you say there was a signpost marked DANGER?â Mr. Hardy asked curiously. âWhere?â

Frank pointed toward the top of the embankment. âThe one rightââ His words trailed off.

âWhyâitâs gone!â Joe exclaimed.

The boys led the way up the embankment. Then they slowly walked along the shoulder of the road. In a minute they discovered a small hole that had been hastily filled in.

âHereâs the place,â Frank said. âThis is where we saw the sign.â

âIâd call it a sinister signpost,â Mr. Hardy remarked, rubbing his chin dubiously. âItâs here one minute, and gone the next. Obviously someone has carried it off.â

Joe casually thrust his hands into the pockets of his jacket. A moment later his face showed surprise and he pulled a piece of paper from one of his pockets. On it was a printed message:

THIS IS A FINAL WARNING!
HANDS OFF THE ALDEN CASE!

âThis must have been put in my pocket while we were lying at the bottom of the embankment,â Joe said.

âWe can be sure of one thing,â Frank added. âWhoeverâs after Mr. Aldenâs experimental motor is also responsible for the accidents.â

A car roared up and screeched to a halt. Its driver, one of Aldenâs race car mechanics, leaped out.

âMr. Alden!â he shouted excitedly. âWe just received a call from one of your watchmen at the plant. The research department is on fire!â

âWeâll drive you there,â Mr. Hardy offered. âThere might be a connection with the accident here.â

He and his sons hopped into the boysâ convertible with Alden. By the time they arrived at the plant, the flames were completely extinguished. Firemen began to rummage through a charred area that once was Aldenâs research shop.

âThis is a terrible blow to my experimental project,â he muttered.

The Hardys expressed their regret, then went to talk with the fire chief.

âI canât say what caused the fire,â the chief told them. âWeâll have to conduct an investigation first.â

âApproximately when did it start?â Frank asked.

âWe got the alarm about an hour ago.â

âIâd appreciate knowing the results of your investigation,â Mr. Hardy said as he presented his credentials to the fire chief.

The man recognized the name immediately. âIt sure is a pleasure to meet you, sir. And these two boys must be your sons, Frank and Joe. My nameâs Fred Evans.â There was an exchange of handshakes. âYou can count on me,â the fire chief continued. âIâll let you know if we uncover anything.â

The Hardys thanked him, then rejoined Alden who was picking his way through the rubble of his burned shop.

âThereâs nothing left to salvage,â he said dejectedly. âHowever, Iâll set up a temporary research shop in one of the other buildings.â

The Hardys expressed their regrets at Aldenâs loss and returned home. Aunt Gertrude was still greatly upset over her inheritance of a stable filled with retired race horses.

âFenton!â she exclaimed. âYou promised to call the attorney whoâs handling the estate, and you never did. Please do it right away. I canât rest thinking about that awful place.â

Mr. Hardy went to telephone, while the boys had a snack of sandwiches and milk in the kitchen. A few minutes later their father hurried into the room.

âI still have the attorney on the line,â Mr. Hardy said. âHeâd like us to take a look at the stables. However, I have too much work to clean up here, and Iâm sure your aunt wonât go. So why donât you two boys hop down to Maryland?â

âSure thing, Dad,â Frank replied.

Mr. Hardy completed his call, then gave Frank and Joe their instructions.

âYou can catch an early train to Baltimore in the morning,â the detective explained. âThe attorney will meet you at the station there. Heâll be waiting in front of the information desk. His name is Steve Benson.â

Frank and Joe left Bayport aboard the seven-oâ clock train. It was nearly noon when they arrived in Baltimore. The boys went directly to the information desk and noticed a tall, even-featured man standing nearby. He appeared to be in his late fifties, and was impeccably dressed.

âMr. Benson?â Frank queried.

âYes,â the man answered. âAnd you must be the Hardys. Iâve heard a lot about you and your father.â He extended his hand in greeting. âMy car is just outside. The stable isnât far from here.â

The boys enjoyed the drive through the lush, green countryside. During the journey, the attorney discussed Aunt Gertrudeâs situation.

âYour father says that she wants to sell the stable as soon as possible,â Benson remarked. âWe shouldnât have any trouble doing that. In fact, Norman Fowler, the temporary manager out there, would like to buy the place. Unfortunately he doesnât have the money right now.â

Nearly an hour passed before Benson guided his car through an arched gateway. Spread across the arch, in gold letters, was the name:

SOUTHERN PINES STABLES

âAll told, there are about twenty acres here,â the attorney announced. âItâs not very big, but itâs adequate for the purpose.â

Ahead, the boys saw a small house and two other wooden structures. All were painted white and appeared to be in excellent condition. The largest of the buildings contained the stalls for the horses. To the left was a large grassy area surrounded by a wooden fence. About a dozen fine-looking horses were lazily grazing there.

Benson brought the car to a stop near the house and got out. The young detectives followed. Standing on the porch was a bulky, deeply tanned man whom the attorney introduced to the boys as Norman Fowler.

âThe Hardys have come to take a look around,â Benson told him.

âGlad to be of service,â Fowler said cordially. âAs you probably know, all the horses here have seen the last of their racing days. The owners want to provide a comfortable retirement for them. Thatâs our job.â

The manager invited his guests into the house to lunch, then took them on a tour of the stables. As the day drew to a close, Fowler suggested that the boys remain overnight and return to Bayport in the morning.

âAll my stable hands are away for the evening at a local affair,â he said, âand the bunkhouse is empty. You can sleep there.â

Benson announced that he had to leave, but promised to return in the morning to drive the Hardys to the railroad station. After a quick supper prepared by Fowler, Frank and Joe went to the bunkhouse. At ten oâclock they retired for the night. Little more than an hour had passed when the boys were awakened by the muffled sound of men talking.

âThatâs odd,â Frank whispered. âI thought all of Fowlerâs stable hands were away for the evening.â

The boys dressed and crept out of the bunkhouse toward the source of the voices.

âWe want fifty percent of the take,â they heard one man say.

Joe accidentally stepped on a twig, which snapped with a cracking noise. The boys froze in their tracks and listened. There was only silence.

âLetâs move ahead and try to get a glimpse of the men,â Frank hissed.

The young detectives cautiously edged their way through the darkness. They saw no one. Then suddenly a voice boomed out from behind them.

âStay where you are!â

The boys turned to find themselves peering into the muzzle of a rifle.

âWho are you?â Joe demanded.

The armed man directed the beam of a flashlight into the faces of the Hardys.

âOh, itâs you boys,â he said. âI thought you were asleep.â The man flicked the beam of light onto his own face.

âMr. Fowler!â Frank exclaimed.

âWe heard some men talking out here,â Joe explained, âand came to investigate.â

âDid you see them?â the manager questioned.

âNo,â Frank replied. âWe never got close enough.â

âWell, I heard them too,â Fowler said. âBut Iâm sure they were workers from the farm just across the way. They often use our area as a short cut when they walk back from town.â He then said good night and went into the house.

Frank and Joe rose early the next morning. They had just finished breakfast when Benson arrived to take them to the railroad station. The boys thanked Fowler for his hospitality, then hurried off to the train. During the drive, the attorney explained some of the legal points involved in their auntâs intended sale, and handed them some documents that she was to examine.

When they arrived in Bayport, the boys wasted no time in telling Aunt Gertrude and their parents what they had seen.

âItâs too bad you want to sell the stable,â Joe said. âThe place is beautiful.â

âSay no more!â their aunt retorted. âJust give me the documents the lawyer wants me to read, so I can get it over with!â

âOnce your aunt makes up her mind,â Mr. Hardy commented, âthereâs no changing it.â

The following morning Alden telephoned Mr. Hardy. âCome to the Clayton Police Station right away,â he requested. âThereâs a thief down here whoâs been stealing information on my experimental motor!â

CHAPTER VII

The Elusive Stranger

MR. HARDY and the boys drove to Clayton immediately. Alden met them at the police station.

âWhere is the suspect?â Mr. Hardy asked him.

âDetective Lieutenant Swaze is questioning him in the interrogation room,â Alden answered. âHe said we were to join him the minute you arrived.â

Inside, a thin, untidily dressed man was seated in a chair. Lieutenant Swaze, lanky and middle-aged, was pacing the floor in front of him. Alden introduced the detective to the Hardys.

âThis man is charged with burglary,â Swaze announced. âHe was caught rifling Mr. Aldenâs office safe by one of the watchmen at the plant.â

âWhen the police searched him,â Alden interrupted, âthey found several hollow-core impeller blades for my experimental motor in his pocket. I always keep a supply of them in the safe until an engine is ready for assembly.â

Mr. Hardy turned to the suspect. âWhom are you working for?â he demanded.

âI ainât workinâ for nobody!â the prisoner shouted. âAnd I donât know nothinâ about any experimental motor!â

âThen why did you take the impeller blades?â Frank asked quickly.

âThem things were made out oâ shiny metal,â the man replied nervously. âI thought it might be silver and I could get some money for âem.â

The interrogation continued for another two hours. The prisoner stuck to his story. Finally the boys and their father left the room with Alden.

âIâm convinced the suspect is telling the truth,â Mr. Hardy concluded. âHeâs obviously just a small-time crook who would steal anything.â

âThen you donât think heâs part of a gang trying to get the plans for my motor?â Alden queried.

âAt this point, no,â the detective said. âBut letâs see what the police come up with when they check his record.â

Alden glanced at his watch and announced that he would have to return to the plant. The Hardys walked to their car and started back to Bayport, disappointed that nothing had come of their trip.

While driving through the center of Clayton, Joe suddenly pointed toward two men standing on a street corner. âLook!â he exclaimed. âThereâs Barto talking to someone!â

âI wonder why heâs not at work,â Frank remarked.

âMaybe he has the day off,â Joe answered.

The boys noticed that Bartoâs companion had the collar of his jacket turned up high, and his hat pulled low over his eyes.

âThat guy heâs with sure looks suspicious,â Joe commented.

Frank stopped the car at the next corner. âIâll walk past Barto and try to get a glimpse of the other manâs face,â he said. âThe sidewalk is crowded with pedestrians. Chances are he wonât spot me.â

Frank made his way toward the two men. When he was within a few feet of them, Barto suddenly gave his companion a hard shove. The man turned and ran down the street. Frank, figuring this was strange, raced off in pursuit.

âDid you see that?â Joe said to his father.

âYes! Come on! Frank might need our help!â

They leaped out of the car and joined in the chase. Mr. Hardy stopped long enough to fire a question at Barto.

âWho was that man you were talking to?â

Barto appeared surprised. âIâI donât know,â he stammered. âHe was looking for a handout. When I refused, he insulted me and I gave him a shove.â

Mr. Hardy hurried on and found his sons standing at the entrance of an office building.

âHe ran in here,â Frank told his father.

âLetâs go after him!â Joe urged.

âIâll stay outside,â Mr. Hardy said. âIn case he gives you the slip, Iâll go after him.â

The boys ran into the building and discovered that the elevator was out of order. They bounded up the stairs. High above them, the two sleuths heard heavy footsteps.

âHe must be heading for the roof!â Joe whispered.

Continuing the chase, the boys soon reached the roof. Their quarry was not in sight, but they heard what sounded like a metal door being slammed shut.

âIt came from over there!â Joe said, pointing to the roof of an adjacent building.

The boys leaped across the narrow gap separating the two structures, and found a door leading inside. Pulling it open, Frank and Joe rushed down the stairs to the ground floor. Their father met them as they dashed outside.

âYour man came running out of this building,â Mr. Hardy said. âI was too far away to stop him. By the time I realized what had happened, he disappeared in the crowd.â

âToo bad,â said Frank.

As the Hardys drove home, the detective told his sons what Barto had said.

âDo you believe him?â Frank asked.

âWe have no choice but to take his word for it,â Mr. Hardy replied. âYet Barto doesnât strike me as the type that goes shoving people around.â

âAnd why would a man just asking for a handout run off like a fugitive?â Joe interjected.

âThereâs something fishy about this,â Frank added.

The Hardys had just finished supper when the telephone rang. Frank answered.

âThis is Mr. Alden,â the caller said. âI have one more completed race car fitted with my experimental engine. Luckily it was in the garage when the research shop burned down. I plan to give it a test run tomorrow.â

âAnother competition?â Frank asked.

âNo, this will be a private test. I have permission from the highway department to use a straight stretch of road near the plant. Iâd like you boys and your father to be present. I donât expect any trouble, but it pays to be safe.â

âWouldnât it be better to use the drag strip at your track?â Frank suggested. âYouâd be less likely to find intruders there.â

âThe strip is too short for my purpose,â Alden explained. âShall we say ten oâclock tomorrow morning?â

âWeâll be there,â Frank assured him.

The next day the boys and their father drove to the test site. Aldenâs experimental race car was unpainted, and its highly polished metal surface gleamed in the sun. Mechanics were giving the vehicle a final inspection.

âWeâll be ready to start in about twenty minutes,â Alden told the boys. âI intend to drive the first couple of runs myself. They will be acceleration tests.â

He said that the car was a two-seater designed to carry a mechanic in addition to the driver.

âSince I wonât be taking a mechanic with me,â Alden said, âhow would one of you boys like to go along?â

He suggested that the boys draw straws to decide which one would accompany him. They did, and Frank won.

âThatâs settled,â Alden remarked, then added, âJoe, would you mind helping us with the tests?â

âHow?â

âNormally, thereâs not any traffic using this road,â Alden replied. âBut we canât be sure. So Iâd like to post a man with a walkie-talkie at the far end of the stretch to warn me if anything comes along. I have a radio receiver in the car for that purpose.â

âIâm your man,â Joe assured him.

He could not help but feel a bit envious of his brother as he watched Frank climb into the sleek car with Alden. Mr. Hardy drove Joe to his post a couple of miles down the road, which at that point was flanked by heavy woods.

As the detective drove off, Joe heard a voice crackle from the speaker of his walkie-talkie. âAll clear ahead?â

âAll clear!â

Minutes later, Joe could detect the sound of Aldenâs car approaching. Then he spotted it far down the road. It was a shining speck of silver that grew larger and larger each second.

As Joe watched, he was startled to see a battered automobile emerge from the woods.

âStop!â Joe cried frantically. âMr. Alden, stop!â

CHAPTER VIII

Stolen!

THE dilapidated car turned onto the road, picked up speed, and headed directly for Aldenâs car. Joe raced after it, calling out into the walkie-talkie.

His pleas went unheeded. Joe was horror-stricken at the small gap between the two vehicles. A head-on collision seemed inevitable.

âFrank! Mr. Alden!â Joe screamed. âWatch out!â

Suddenly the mystery car swerved out of control. It went hurtling off the road and tumbled over into a ditch. A split second later the vehicle was a mass of flames.

Alden brought his racer to a screeching halt. He and Frank leaped out and followed Joe toward the disabled vehicle. They managed to get close enough to pull open one of its doors. The three were amazed to find that there was no one inside.

âGet back!â Alden shouted. âThe gas tank may explode any second.â

His warning came just in time. As Alden and the boys got clear, there was an explosion. A large ball of orange flame rose above the burning car. It quickly transformed into a thick cloud of black smoke.

Minutes later a pickup truck arrived on the scene, carrying a crew of Aldenâs mechanics. Mr. Hardy was with them. The men scrambled out with fire extinguishers, and directed streams of chemical foam at the burning car. Soon the flames and smoke disappeared.

âYou gave us a bad scare,â Mr. Hardy said, turning to Frank and Alden. âWe saw the smoke and came running. We thought youâd had an accident with the car.â

âThey almost did,â Joe said shakily. He told his father what had happened.

When the car cooled sufficiently to be touched, the Hardys examined it. The heat had turned the vehicle into a charred mass of twisted metal.

Frank, looking underneath, made a startling discovery. To the underside was attached the remains of an elaborate radio-controlled system. Wires ran from it to the throttle and steering mechanism.

âSo thatâs how the car was operated with no driver!â Joe exclaimed. âBut why did it go hay-wire all of a sudden?â

Frank had an answer. âWhen Joe used the walkie-talkie to warn us, the signal must have interfered with the radio frequency used to guide the car.â

Mr. Hardy nodded. âWhoever operated the transmitter would have needed a clear view of the road, and at a point not too far away from this spot.â

Frank looked toward a high hill, the top of which loomed above the treetops. âThereâs a perfect spot,â he said, pointing to it.

The boys lost no time in climbing to the summit to investigate. The area was covered with thick brush and grass.

âThese bushes would provide good cover for anyone watching the road,â Frank stated.

âLook! Over here!â Joe cried out. âSome of the grass has been trampled flat. Iâd say it was done recently by two or three men.â

Frank examined the spot. âThis is where the transmitter was set up,â he concluded. âFrom here you get a perfect view of the road.â

A further search revealed no other clues. The boys rejoined their father and Alden. Mr. Hardy stated that he had given the mystery car a thorough going-over, but found nothing that would permit them to trace its owner.

âThe vehicle wasnât carrying license plates, and the serial numbers on the engine and chassis had been removed,â he continued. âAlso, the fact that it was burned to a crisp doesnât help either.â

Alden decided to carry on with the tests. When he had finished, the Hardys offered to drive him to his office.

As they started off, Alden rested back in the seat. âAfter all the excitement weâve been having lately, I need a little diversion,â he said. âI think Iâll spend Saturday giving my race horse a work-out.â

âRace horse?â Joe queried.

âYes,â Alden answered. âIâm interested in racing of all kinds. I bought the horse several months ago. Great animal! I keep him in a rented stable near the plant.â

âOur aunt would tell you off quick if she knew this,â Frank remarked laughingly. He then told Alden about Gertrude Hardyâs recent inheritance.

âA stable for retired race horses? Sounds like a great idea,â Alden said. âIâll keep it in mind. Perhaps someday Iâll send my horse down there.â

âNot if Aunt Gertrude has anything to say about it,â Joe muttered with a grin. âAnyway, she will have sold her stable by that time.â

Alden asked the Hardys if they would like to see his horse. The boysâ father had to decline because of a business appointment, but Frank and Joe eagerly accepted the invitation.

âAnd would you mind if we bring our friend Chet?â Frank asked.

âPlease do,â Alden replied. âDrop by any time. Iâll be at the stable most of the day.â

Chet was not able to go until the afternoon because of Saturday chores to do. The Hardys picked him up at the Morton farm.

âA real race horse, eh?â Chet said with a grin. He pulled three apples from his pockets and offered one to each of his friends. âWhat I wouldnât give to own one!â

When they arrived at the stables, Alden was leading a beautiful, haltered thoroughbred around the paddock. His owner spotted the boys and led the animal toward them.

âHow do you like him?â he called out. âHis name is Topnotch.â

âNice piece of horseflesh,â Chet commented, trying to act like a seasoned equestrian.

The horse was completely chestnut in color, except for small white areas above its two front hoofs. The boys watched in admiration as Alden removed the halter and permitted Topnotch to trot freely around the paddock.

As Joe glanced toward a row of stalls nearby, he noticed a sandy-haired young man pitching hay into one of them.

âMr. Alden, isnât that your son Roger over there?â Joe asked.

âYes,â Alden replied in a determined voice. âI arranged to get him a job here so he could help pay for the race car he damaged. Itâs about time he developed a sense of responsibility. Iâd have given him something to do at the plant, but he canât get along with the other workers.â

Chet followed the Hardys to the stall.

âHello, Roger,â Frank said in a friendly voice.

The young man looked surprised. Then his eyes narrowed as he glared at the boys.

âOh, itâs you guys again!â he snapped. âYou keep popping up like bad dreams.â

âSo youâre still carrying a chip on your shoulder,â Joe retorted.

âYou bet I am,â Roger shot back angrily. âIâve got to work in this lousy place to pay for that stock-race car I had an accident in. You Hardys were the cause of it all!â

Frank kept his temper, but said, âDonât tell us youâre sticking to that fairy tale of yours. You know we didnât reflect sunlight into your eyes while you were driving.â

âItâs my word against yours,â Roger snarled. âBut what chance do I stand? Because youâre the Hardy boys you think you can get away with anything.â

Joeâs face flushed with anger. However, he managed to exercise self-control. âItâs useless trying to talk sense into Roger,â he said. âWeâd better go.â

As they walked away, Chet remarked, âThat fellow is about as friendly as an enraged cobra.â

Roger, who overheard the comment, gave Chet a black look. He picked up a large mass of hay with his pitchfork and flung it on top of the chubby youth.

Chet scrambled from underneath the pile. He quickly brushed strands of hay from his eyes, ears, and hair. Then, angry, he grabbed a feed bag nearby and pulled it over Rogerâs head, down to his elbows. The imprisoned boy stumbled around the stall in a frenzy.

âIâll get you for this!â Roger yelled after his tormentor when he finally pulled the bag free.

The Hardys and their chum strolled back to the paddock. Mr. Alden had been too preoccupied with Topnotch to notice what had happened.

âLetâs not say anything to him about Roger,â Frank suggested.

The boys spent the balance of the afternoon watching Alden exercise his horse, or taking turns riding the mount themselves.

âHeâs super,â Chet remarked. âSure beats our farm horses.â

At sundown the boys thanked the owner and left.

Frank and Joe spent a relaxing Sunday at home and retired early. The family had been asleep only a short time when the telephone rang. Frank got up and rushed to answer it. His father had already picked up the extension by his bed.

âThis is Alden,â an excited voice was saying. âSorry to disturb you. But something terrible has happened and I need your help. Iâm at the stable. Topnotch has been stolen!â

CHAPTER IX

Demand for Ransom

FRANK wakened his brother to tell him about Topnotch. The boys and their father dressed quickly, rushed to their car, and headed for the stable.

âThis sounds to me like some of Rogerâs work,â Joe suggested.

âPossibly,â Frank agreed. âHeâs pretty mad at his father. Roger could have done it for spite. But stealing a horse is not easy. Heâd need help.â

âMy advice is to wait until we get the facts before coming to any conclusions,â Mr. Hardy interjected. âI realize Roger would never win a popularity contest. Yet itâs hard to believe heâd be mean enough to do a thing like this.â

They arrived at the stable to find Alden still greatly distraught over the theft of his horse.

âThe police were here to investigate,â he told the Hardys. âThey left a few minutes ago.â

âWhat did they come up with?â Joe asked.

âNothing,â Alden replied disappointedly. âThe thieves were careful not to leave a shred of evidence behind. Even the foot- and hoofprints leading from Topnotchâs stall were swept away.â

âBut they must have used some kind of a vehicle to carry the horse off,â Frank said. âDid the police find any tire tracks in the area?â

Alden nodded and asked the Hardys to follow him. After walking a short distance, he directed the beam of his flashlight toward the ground and pointed to a set of deep, parallel ruts pressed into the soft earth.

âThey must have been made by a truck or a horse van,â Joe said.

Mr. Hardy stooped down and examined the ruts carefully. âObviously the thieves covered the wheels with canvas or other heavy material,â he concluded. âThere arenât any tread marks. Too bad.â

âWere there any witnesses to the crime?â Frank queried.

âOnly one of the grooms,â Alden answered. âBut he canât help us. He lives in a room above the stable. When he heard a strange noise in one of the stalls, he came down to investigate and was struck from behind. The police took him to the hospital.â

âHas the groom been able to tell when the theft took place?â Mr. Hardy questioned.

âYes. He regained consciousness. The theft was about five hours ago. The groom had been tied and gagged. It took him over four hours to work himself free after he regained consciousness.â

Joe let out a whistle. âFive hours!â he exclaimed. âThe truck could be hundreds of miles away by now.â

The Hardys did not want to upset Alden any further by asking him about Rogerâs whereabouts that evening. Instead, they discussed the case from another angle.

âWe donât know if this was an inside job or not,â Mr. Hardy remarked. âBut we can be reasonably sure what the motive is. Ransom!â

âIn that case, the thieves will try to contact me,â Alden said. âIf they do it by telephone, theyâll call my office, since I have an unlisted number at home.â

âI suggest we go there right away and wait,â Frank put in. âThe horsenappers may start early to call.â

Alden accompanied the Hardys in their car. During the drive, Mr. Hardy outlined a basic plan.

âIf you should receive a call demanding ransom,â he advised the horseâs owner, âstall him off. Tell him you want proof that they actually have Topnotch. Thatâll give us more time to hunt a lead.â

Arriving at the plant, Alden led the way to his office. There he and his companions each selected a comfortable chair and settled down to wait.

âHave you a private line here in addition to your regular company phone?â Mr. Hardy asked the executive.

âYes, I do,â Alden replied, pointing to one of two phones on his desk.

âGood,â the elder detective said. âIâll use it to have the call traced if the thieves should contact you.â

The night dragged on slowly. The boys were restless and found it difficult to sleep. When morning finally came, Alden arranged to have breakfast served in his office.

It was a little after nine when there was a short buzz on the company phone. Alden scooped it up, listened for a moment, then covered the mouthpiece with his hand.

âItâs my secretary in the outer office,â he informed the Hardys. âShe says a man wants to speak to me. He refuses to identify himself.â

âThis might be the call weâre waiting for!â Joe exclaimed softly.

Mr. Hardy rushed to the private phone. âIâll get to work on having the number traced,â he announced quickly. Seconds later, he signaled Alden to proceed.

âOkay, put him on,â Alden ordered his secretary

The boys fixed their eyes on the executive and waited anxiously.

Alden suddenly sat bolt upright in his chair. âYou want fifty thousand dollarsâ ransom to return Topnotch?â he shouted into the phone. âYouâre out of your mind! Iâd want absolute proof before I handed out that kind of money!â

A few seconds later the executive placed the phone down. âHe hung up,â Alden announced.

Mr. Hardy frowned. âToo bad. There wasnât enough time to trace the call. Obviously weâre not dealing with amateurs.â

âWhat did he say when you asked for proof that they had Topnotch?â Frank put in.

âHe said heâd think about it and let me know later,â Alden replied.

Mr. Hardy stretched out his arms and yawned. âYou boys must be as exhausted as we are,â he said. âWhy donât you go home and get some rest? Iâll stay here. Youâll hear from me immediately if anything comes up.â

His sons readily agreed. But it was not rest that interested them. Their fatherâs suggestion offered an excellent opportunity for them to question Roger without Aldenâs knowledge.

âLetâs go back to the stable and see if heâs working today,â Frank said as they drove off in their convertible.

When the Hardys arrived, Roger was busy painting a section of the fence that surrounded the paddock.

âWeâd like to ask you a few questions,â Frank called out.

Roger quickly glanced at his visitors without interrupting his work. âItâs you guys again!â he snapped. âHavenât you got a home? Get lost! I donât have time to answer any of your stupid questions.â

âCome off it!â Joe shot back angrily. âYou must know your fatherâs horse was stolen last night. Thatâs what we want to ask you about.â

There was a momentary pause. Roger nervously fingered his paintbrush and kept his face turned away from the Hardys. âYes, I heard about it,â he muttered defiantly. âBut youâve come to the wrong guy for information. And even if I did know something about it, I wouldnât tell you.â

âWhere were you last night?â Frank demanded.

âWhy donât you try looking into a crystal ball to find out?â the young man retorted.

âCut the comedy!â Joe exclaimed. âThis is serious. A theft has been committed, and thereâs no reason why you shouldnât be among the suspects.â

âOkay! If you have to know, I was working on my dragster all evening,â Roger snapped.

âWhere?â Frank questioned.

âAt home!â

âCan you prove it?â Joe asked. âI mean, was there anyone with you who can back up your statement?â

âYou want fifty thousand dollarsâ ransom?â Alden shouted

âNo. I was alone,â Roger answered.

âWhat about your father?â Frank put in. âDidnât he see you?â

âHe was visiting friends till late. I was already in bed when he got home.â

âFor your sake,â Joe remarked, âI hope youâre telling the truth.â

Roger suddenly hurled his paintbrush to the ground. His face was flushed with anger. âIâve had enough of you two!â he rasped. âWhat I do is none of your business!â

âWeâre making it our business,â Joe told him.

Frank wanted to avoid a scene. âSimmer down,â he said calmly. âWeâll have to take your word for what you told us. But if you should run across any information concerning the theft, I advise you not to keep it to yourself.â

The Hardys walked back to the convertible and returned to Bayport. Their mother and aunt were disappointed to see that the boysâ father had not come with them.

âI suppose heâs chasing after some horrible criminal!â Aunt Gertrude remarked. âYour father wonât remember where he lives if he keeps up this sort of thing.â

âNow calm down, Gertrude,â Mrs. Hardy pleaded in a soft voice.

Joe playfully sniffed the air. âSmells like roast turkey for supper.â

âAnd coconut-custard pie for dessert,â announced Mrs. Hardy.

âLetâs hope your sons can stay put long enough to eat it,â said Aunt Gertrude.

The boys went to bed early that night. They spent the next day puttering around their crime lab and mulling over the case. It was midafternoon when their father telephoned with an urgent message.

âMr. Alden just received another call from the thieves,â said the detective. âHe was told that the proof he had asked for would be found in a book entitled Famous Horses of the World, at the Clayton Library. Meet us there just as soon as you can.â

The boys started out immediately. At the library they found their father and Alden seated at one of the reading tables examining a large book.

Mr. Hardy handed his sons a photograph. âThis was tucked in between the pages,â he whispered.

The boysâ eyes widened with surprise. âItâs a picture of Topnotch,â Frank said.

âAre you absolutely sure?â Joe asked.

âNo doubt about it,â Alden replied in a low voice.

âAnd itâs a cul-de-sac when it comes to getting a line on who placed the photograph in the book,â Mr. Hardy said. âI questioned the librarian, but she has been too busy to take note of any strangers.â

âMay we keep the picture for a while?â Frank queried. âIt might provide us with a clue.â

âYouâre welcome to it,â Alden replied. He glanced at his watch. âIâd better get back to the plant. The thieves will surely call me again.â

Mr. Hardy explained that Alden had had one of his drivers bring them to the library. He turned to the executive. âWhy donât you send him back to the plant? You and I can go along with the boys in their car.â

âVery well,â Alden agreed.

As they drove, Mr. Hardy urged his client to stall for more time. âTell those crooks that you canât get the ransom money until Friday morning,â he said.

âIâll try.â Alden sighed. âBut I donât want to endanger Topnotch any more than I have to.â

Soon the plant came into view. As they drove toward the main gate, Aldenâs experimental race car suddenly sped out of the driveway.

âI didnât give anyone permission to drive that car!â he shouted.

Frank pressed down on the gas pedal and the convertible shot off in pursuit!

CHAPTER X

Suspicious Rendezvous

âTHAT racer is too fast for us!â Joe yelled. âWeâll never catch it.â

âTurn onto that side road just ahead!â Alden ordered. âWe might be able to head him off!â

Frank followed instructions. It was a wild, bumpy ride and kept the occupants hanging on to their seats. After a couple of miles, the route led them back to the road along which their quarry was traveling.

âThereâs the experimental car!â Mr. Hardy called excitedly as he peered out the rear window. âItâs about quarter of a mile behind us and coming fast!â

Frank skillfully maneuvered his convertible to prevent the other driver from passing.

âHang on!â he cried out. âIâm going to start slowing down!â

As the Hardy car came to a stop, the other driver was forced to do the same.

âGood work!â Alden exclaimed, and leaped out of the convertible. The Hardys followed.

âRoger!â Joe exclaimed as a sandy-haired young man slowly emerged from the experimental dragster.

Alden was furious. âWhat do you think youâre doing?â he demanded.

âIâI was just taking your car for a little spin,â his son stammered.

âWhy arenât you working at the stable?â Alden fumed.

âI took the afternoon off,â Roger replied.

Alden glared at his son with a look that would melt ice. âYou know my racer is a secret project. How dare you take it for a drive?â

He turned to the Hardys. âIâll meet you back at my office. Iâm going to ride to the plant with Roger just to make sure he doesnât get any more wild ideas.â

The Hardys reached the office just as Alden finished reprimanding his son.

âDonât send me away to that lumber camp,â Roger was pleading.

âI donât see what else I can do with you,â his father replied. âIâm fed up with your shenanigans!â

âBut I promise to stick with my job at the stable,â Roger replied, âand I wonât go near your experimental car again.â

Alden rubbed his chin dubiously for a moment. âWellâall right,â he finally agreed. âBut step out of line once more and off you go.â

Roger thanked his father. Then he rushed past the Hardys and out of the office.

At that instant the telephone rang. Alden picked it up. From his expression the Hardys knew it was another call from the thieves.

âYes, I saw the photograph of Topnotch you placed in the book at the library,â Alden informed the stranger.... âWill I pay the ransom you demand? I suppose Iâll have to. But you must give me until Friday. Itâll take me that long to get such a large sum of money.â

When the telephone conversation ended, Alden glanced at the Hardys. âTheyâve agreed to wait till noon on Friday. Iâm to receive further instructions then.â

Frank jumped up. âThat gives us two and a half days to find out who stole your horse.â

âWeâll get to work on it right away,â Mr. Hardy said.

âI hope youâre successful,â Alden commented. âFifty thousand dollars is a lot of money. But Iâll pay it if I have to.â

The Hardys hurried home to Bayport. There the elder detective began going through his criminal files. âIâll check to see if I have information on anyone whose specialty is horsenapping,â he said.

Meanwhile, his sons hurried off to their crime lab and studied the photograph of Topnotch.

âWhat are we looking for?â Joe inquired.

âI thought we might find something in the picture that would help us identify the locality,â Frank replied.

âSlim chance. Other than the horse, thereâs nothing but a few bits of shrubbery.â

âWait a minute! Thatâs it! Perhaps a botanist could tell us if the shrubs are indigenous to a particular region.â

âLetâs call Mr. Scath, curator of the Howard Museum.â

Frank rushed to the phone and dialed a number. Soon he had the curator on the line.

âWe recently added a botanist to our staff,â Scath said. âHis name is Mr. Ronald Clause. Iâm sure he can be of help to you.â

âWould it be possible to see him right away?â Frank asked. âItâs urgent.â

âYes,â the curator assured him. âWeâre about to close the museum for the day, but Mr. Clause plans to be here for a couple of hours to work on a new exhibit. Iâll tell him youâre coming.â

The boys hurried to their car and drove to the museum, located in the northwestern section of Bayport. A lanky, scholarly-looking man admitted them.

âIâm Mr. Clause,â he announced. âMr. Scath said you wanted to see me.â

The boys introduced themselves, then stated their business. They handed the botanist the photograph of Topnotch.

âHm! The shrubs are a bit out of focus,â Clause muttered, âbut Iâll see what I can do.â

âWe realize youâre very busy,â Frank said. âHowever, weâre racing against time. Weâd appreciate it if you could give us an answer as soon as possible.â

âIâll get to work on it right away,â the botanist answered. âMight take me a day or so. If I come up with something, Iâll call you.â

The Hardys thanked him and left. As they drove back home, Frankâs thoughts returned to Aldenâs son.

âIâm still not convinced that Roger had nothing to do with the theft of Topnotch,â he remarked.

âIâm not either,â Joe added. âSay, why donât we shadow him tomorrow? If he is in with the crooks, he might try to contact them.â

âWeâve nothing to lose,â Frank agreed. âBut it would be safer to have Roger shadowed by someone he doesnât know. That eliminates us and Chet.â

âWhat about Biff Hooper and Tony Prito?â Joe suggested. âTheyâve done a good job of following suspects for us before.â

âGood idea. Letâs call them when we get home.â

Like Chet, Biff Hooper and Tony Prito were classmates of the boys at Bayport High. They always welcomed a chance to work with the Hardys on their cases.

âWhatâs up?â Biff asked eagerly as he and Tony joined the Hardys in their crime lab. âFrom your telephone call, Iâd say it was important.â

âIt is,â Frank assured him. âAnd we need your help.â

Tony Prito, a dark-haired, lively boy, declared, âCount me in!â

Frank and Joe gave their friends a quick rundown on the case, then furnished them with a description of Roger.

âWeâd like you to shadow him and give us a report on everything he does,â Joe said.

âYouâll find Roger at the stable in the morning,â Frank added. âTry to be as inconspicuous as possible. We donât want him to suspect heâs being watched.â

Biff, a tall, blond, athletic-looking youth, beamed with enthusiasm. âYou can depend on us!â he exclaimed.

The next day the Hardy boys stayed close to the telephone. It was almost one oâclock in the afternoon when a call came. Frank answered.

The caller was Biff Hooper. âTony and I followed your suspect to a restaurant in Clayton. Heâs inside talking to a couple of suspicious-looking characters.â

âAre you calling from the restaurant?â

âNo. Iâm in a public phone booth across the street from it, on the corner of Stanton and Winthrop streets.â

âJoe and I will come there right away!â Frank declared. âIf Roger leaves in the meantime, stick with him. You can let us know where you are by leaving a message with Mother or Aunt Gertrude. Weâll check with them every fifteen minutes.â

The boys leaped into their car and headed for Clayton. When they arrived, Biff and Tony were still at their posts across the street from the restaurant.

âYour suspect hasnât left yet,â Biff said.

Frank pointed to a building behind him. âLetâs hide in that doorway, Joe,â he advised. âWe donât want Roger to spot us when he comes out.â

The Hardys and their companions became impatient as the minutes ticked by. Finally Roger emerged from the restaurant with two rough-looking men. Each of them walked off in a different direction.

Frank turned to Biff. âYou and Tony follow Roger,â he ordered. âJoe and I will split up and trail those two men he was with.â

Each boy hurried off on his assignment. Frank trailed his quarry for several blocks. Suddenly the man darted into an alley.

âHe must know heâs being followed,â the young detective thought, and cautiously stalked toward the spot. He peered into the alley. There was nothing in it but a pile of discarded wooden crates at the far end.

âThat man must be hiding behind them,â Frank decided.

As he edged his way forward, the man leaped from back of the crates and flung a small object toward Frank. It hit the ground a few feet from the boy and exploded!

CHAPTER XI

A Prize Catch

A THICK, white cloud of smoke erupted from the spot. Frank felt a burning sensation in his eyes and began to cough uncontrollably.

âItâs tear gas,â he thought. âI must get out of here!â

Frank stumbled backward away from the smoke. At that instant he saw the blurred figure of a man running past him. The young detective lashed out with his fist and made contact. Then someone grabbed his left arm. Again Frank lashed out with his fist, but his punch was blocked.

âHold it!â came the voice of his brother. âItâs Joe!â

As the effects of the tear gas wore off, Frank saw a man lying unconscious on the ground. Joe pointed at the prone figure. âLooks as if you got your man,â he said. âWish I could say the same.â

âYou lost the other guy?â Frank asked.

âI had to let him go. He led me around the block and down this street past the alley. Then the smoke attracted my attention and I saw you were in trouble. So I ran to help.â

The man regained consciousness. âWhoâwho are you guys?â he groaned as he struggled to his feet.

âNever mind that,â Frank answered. âSuppose you tell us who you are?â

âMy nameâs Marty Tempson, if itâs any of your business,â the man growled.

âWhy did you toss that tear-gas bomb at me?â

âI thought you were some guy out for a heist.â

âWhat kind of business did you and your pal have with Roger Alden?â Joe shot at him.

Tempson glared at the boys. âRoger Alden? I donât know no guy by that name,â he snarled.

âYouâre lying,â Frank declared. âHeâs the young man you and your friend were with in the restaurant.â

âNever saw him before,â Tempson replied. âThe restaurant was crowded and he let us share his table.â

At that moment a police patrol car arrived on the scene. One of the officers got out and approached the Hardys and Tempson.

âA shop owner across the street reported seeing smoke in this alley,â the policeman announced. âWhatâs going on here?â

The boys gave their names and Frank explained what had happened. When Tempson was unable to produce identification, the policeman searched him and discovered a tear-gas bomb in his pocket.

âIâm taking you in!â the officer declared.

Tempson turned pale. âYouâyou canât arrest me!â he stammered. âI ainât done nothing!â

âThatâs what you think,â the policeman retorted. âThere happens to be a law against tossing bombs at people.â He glanced at the Hardys. âWill you come to the station and make a statement?â

âGlad to,â Frank answered. âWeâll pick up our car and meet you there.â

Tempson was already being fingerprinted when the boys arrived at Clayton Police Station. The desk sergeant took down their statement, then said that a complete check would be made on the prisoner.

âYou boys must be in court when heâs brought up for a preliminary hearing,â the sergeant added. âThatâll be tomorrow morning.â

âWeâll be here,â Frank assured him.

He and Joe left the building and returned to their car.

âWhatâs our next move?â Joe asked.

âLetâs find out if Roger went back to the stable,â Frank suggested. âIf so, I want to question him.â

Arriving at their destination, the boys found Roger seated in front of a stall repairing a harness. He was as belligerent as ever and became enraged when Frank declared that they had seen him in Clayton with two men.

âYou lousy snoopers!â Roger yelled. âWhat right have you to spy on me?â

âNever mind that,â Joe put in. âWho were the two men you were with?â

âI donât know,â snapped the young man. âI went to the restaurant for lunch. The place was crowded and I let them share my table.â

âVery considerate of you,â Joe said sarcastically. âWhat made you so friendly all of a sudden?â

Roger jumped to his feet. âI donât have to take that from you!â he shouted.

In the next instant he swung the harness at Joe. The young detective stepped back, caught the end of the gear, then wrapped it tightly around his opponentâs arms.

âLet me go!â Roger demanded.

âNot until you calm down!â Joe shot back.

Frank spoke up. âI donât think youâre telling us the truth about not knowing those men.â

âI am!â the young man cried out.

âClayton is about ten miles north of here,â Joe said. âIsnât that a long way to go just to have lunch? Iâve noticed a couple of local restaurants within walking distance.â

âI like the food in Clayton,â Roger replied mockingly.

âWhy did you three walk off in different directions when you left the restaurant?â Frank questioned.

âI went my way, and they went theirs. How am I supposed to know where they were going?â

By now several grooms had collected around the boys. âHey! Rogerâs wisecracking must have finally got him in trouble!â one of them yelled to his companion.

âYeah! And he sure looks funny with that harness wrapped around him,â another said, laughing. âI think he should keep it on permanently.â

Joe felt a bit embarrassed and released Roger, who glared at the faces around him. Then he stormed off.

The Hardys headed back to Bayport. As they rode along, Joe said, âWhat do you think about Rogerâs story?â

âAt least it jibes with what Tempson told us,â Frank remarked. âBut it could have been a prearranged alibi between him and the two men.â

âIf you ask me, thereâs something fishy about the whole thing.â

When the boys got home, they went directly to their fatherâs study.

âGlad to see youâre back,â Mr. Hardy said. âDetective Tanner of the Clayton police telephoned a few minutes ago. He wants to talk to you two.â

âWhat about?â Joe inquired.

âMarty Tempson. Tanner told me all about the tear-gas incident,â their father replied. âThey checked up on him. Seems his name is not Tempson, but Marty Seegan. Heâs wanted in Michigan for robbery.â

âThen it means that Seegan will be extradited,â Frank remarked, âand we wonât have a chance to talk to him.â

âAfraid so,â Mr. Hardy commented. âSince the Clayton police are holding Seegan on a lesser charge, the Michigan authorities get first crack at him. I was also asked to tell you,â the detective continued, âthat the preliminary hearing scheduled in the morning is off.â

At that moment the telephone rang. Mr. Hardy answered it. âItâs for you, Frank.â

âThis is Mr. Clause of the Howard Museum,â the caller announced. âI have some information concerning the shrubbery you asked me to identify in the photograph.â

CHAPTER XII

A Startling Lead

âWHAT did you find out?â Frank asked quickly.

âIâve identified the shrubs as Rubus Diparitus,â Clause told him. âTheyâre indigenous to Maryland and parts of Virginia.â

Frank thanked the botanist for his help. He then informed his brother and Mr. Hardy about Clauseâs discovery.

âMaryland!â Joe exclaimed. âThatâs a coincidence. Aunt Gertrudeâs stable is located there.â

âLetâs go see Mr. Fowler, the manager, first thing in the morning,â Frank suggested. âMaybe he can help us find Topnotch. Is it all right if we have Jack Wayne fly us there, Dad?â

âYou have my okay.â

Jack Wayne, a tanned, lean-faced man, was the pilot of Mr. Hardyâs personal single-engine plane. The boys telephoned him and requested that he be ready for an early departure the next day. Dawn was just breaking as Jack began his take-off roll at the Bayport field.

âToo bad Dad couldnât come with us,â Joe remarked as he watched the ground drop away beneath them.

âYes,â Frank agreed, âbut he wants to be within reach of Mr. Alden if something should come up.â

It took little more than an hour to reach their destination. Jack landed the plane on a small field located about four miles from Aunt Gertrudeâs stable. The airport operator, a genial man, lent the Hardys a car which he kept for the convenience of visitors.

âWe might be gone for several hours,â Frank told the pilot.

âDonât worry about me,â Jack said. âIâll stick around here and do some hangar flying with the fellows.â

As soon as the boys arrived at Southern Pines Stables, they spotted a short, wiry man standing in front of one of the stalls. His hard features and deep-set eyes gave him a foreboding appearance.

âWeâd like to see Mr. Fowler,â Joe informed him.

âWhatcha want to see âim about?â the man asked in a raspy voice.

âItâs confidential,â Frank said. âWeâd appreciate it if you would tell us where we can find him.â

The man stared coldly at the boys for a moment. Then he pointed toward a knoll in the distance. âYouâll find âim on the other side of that hill. Heâs practice shootinâ with his rifle.â

The muffled sound of rifle shots could be heard in the distance. Frank thanked the man and the boys started off. As they crossed over the crest of the hill, they spotted Fowler at the bottom of a shallow gully. He was firing at a paper target.

âWell, if it isnât the Hardys!â Fowler called out when he saw them approaching. âWhat brings you to this neck of the woods? Business?â

âNot exactly,â Frank replied. He then told the manager about the theft of Aldenâs race horse.

âWhy are you telling me all this?â Fowler snapped. âIâve never heard of Topnotch.â

âWeâre pretty sure that the horse is being kept somewhere here in Maryland or Virginia,â Joe explained. âYou must come in contact with lots of stable owners. We thought you might have heard rumors that ...â

âSorry! Canât help you,â the manager interrupted. âMaryland and Virginia cover a lot of territory. That horse could be anywhere.â He squeezed off a couple of shots, then turned to the Hardys. âI regret I canât spend more time with you, but Iâve lots of work to do. Iâm sure you understand.â

As the boys followed Fowler out of the gully, Frank picked up one of the spent cartridge cases from the managerâs rifle. He quickly stuck it into his pocket.

A few minutes later they were back at the stable. The short, wiry man the boys talked to when they first arrived was nowhere in sight.

âSorry to cut your visit so short,â Fowler said, shaking hands with the young detectives. âCome again when Iâm not tied up.â

The boys walked back to their car.

âFowler was certainly in a hurry to get rid of us,â Joe commented. âHe acted mighty suspicious. Why donât we stick around and see whatâs going on?â

âNo. Weâre flying back to Bayport right away,â Frank announced. âIf my hunch is right, weâll save a lot of time in our investigation.â

âWhat hunch?â

Frank dipped into his pocket and pulled out the cartridge case he had picked up. âThis shell is of the same caliber as the one we found the day the smoke bomb was fired into Dadâs study,â he said. âBut I canât tell whether it was fired from the same rifle until I make a microscopic comparison.â

âLeaping lizards!â Joe exclaimed. âIf they do check out, it would connect Fowler with the gang thatâs after Aldenâs experimental motor!â

âAnd the same gang might have stolen Topnotch,â Frank added.

Soon the boys and their pilot were winging back to Bayport.

Mrs. Hardy greeted her sons when they arrived home. âI didnât expect you so soon. Your father left on an errand a few minutes ago. Then heâs going directly to Mr. Aldenâs home. He told me he can be reached there in about two hours.â

The boys hurried to their crime lab. Frank took the first cartridge case he had found, and placed it with the second in the comparison microscope. He peered into the eyepieces of the apparatus for several minutes.

âWhatâs the verdict?â Joe asked impatiently.

Suddenly Frank leaped to his feet. âMy hunch has paid off!â he exclaimed. âTake a look! The markings on the cartridges match exactly!â

âWait till Dad hears this!â

Frank glanced at his watch. âLetâs drive to Aldenâs home,â he suggested. âDad should be there by the time we arrive.â

The boys dashed to their car. An hour went by before they pulled into a driveway leading to a large, white house. It was set back from the road on a spacious, tree-covered lawn.

An elderly servant responded to a single press of the doorbell âWhat can I do for you?â he asked.

âWeâre Mr. Hardyâs sons,â Joe explained. âWe must see our father right away.â

âOh, yes,â the servant answered as he pulled the door open all the way. âHe arrived with Mr. Alden a few minutes ago. Please come in.â

The boys were ushered into Aldenâs study. Mr. Hardy was surprised to see them.

âBack from Maryland already?â he said. âHave any luck.â

âYou bet!â Frank replied excitedly.

Their father and Mr. Alden listened with interest as the two boys told them about their startling lead.

The executive sat bolt upright in his chair. âIf what you suspect about this man Fowler is true,â he said, âthen we must do something right away.â

âIâm going to call Chief Collig,â Mr. Hardy declared. He dialed a number and shortly had the officer on the line.

âThose cartridge cases are strong evidence,â the chief remarked when told about Fowler. âIâll contact the Maryland State Police and have him picked up for questioning. You should hear from me within a couple of hours.â

Alden arranged to have dinner served while they waited. Nearly three hours passed before the phone rang. Mr. Hardy rushed to pick it up.

âThis is Chief Collig,â the caller said. âLooks like your suspect flew the coop. The Maryland police went to the stable and found no one around.â

âIn that case, will you issue an APB on him?â Mr. Hardy asked. âFrank and Joe can give you a detailed description of Fowler.â

âIâll send it out immediately,â Collig assured him.

Frank got on the phone and furnished the police chief with the necessary information. Then he and his companions mulled over the situation.

âNo wonder Fowler was eager to get rid of us,â Joe muttered. âHe was planning a getaway. But we still donât know if he had anything to do with the theft of Topnotch.â

Frank was casually gazing at some photographs mounted on the wall of the study. Suddenly his eyes widened in amazement.

âIâI donât believe it!â he shouted.

CHAPTER XIII

No Trespassing!

âWHAT is it?â Joe asked, surprised at Frankâs outburst.

Frank pointed to a photograph showing a small group of men. âTake a look at the face of the man standing next to Mr. Alden in this picture,â he urged.

Joe peered at the photograph in astonishment. âWhyâitâs Fowler!â he exclaimed.

âThe picture youâre looking at was taken three years ago during a fishing trip I went on with some friends,â Alden interjected as he gazed at the boys curiously. âThat manâs name is not Fowler. Itâs Norman Dodson. Heâs a distant cousin of mine.â

âIâm sure weâre not mistaken,â Frank insisted. âHeâs the suspect weâre after!â

âThe idea is utterly ridiculous,â the executive countered. âWhy would Norman get mixed up with a gang of crooks? Heââ

âThink back,â Mr. Hardy interrupted. âDid you and Dodson ever have a falling-out in the past?â

There was a momentary pause.

âAs a matter of fact we did,â Alden said finally. âAbout a year ago.â

âWhat happened?â Frank asked.

âNorman was once a junior partner in my firm,â the executive explained. âHowever, he became more interested in the raising of race horses than in automobiles. One day he asked to be bought out so he could purchase a stable. Unfortunately, his venture failed and Norman lost all his money.â

âThe pieces are beginning to fit together,â Joe observed.

âThen about a year ago,â Alden continued, âhe came to my office and demanded more money. He said that I hadnât paid him enough for his share in the firm. I refused, and we had a bitter argument. I havenât seen him since.â

âNo doubt about it!â Frank declared. âDodson must have masterminded the theft of Topnotch. And his motive is clear. Heâs out to get more money from you one way or another.â

âI still find it hard to believe.â Alden sighed.

The Hardys returned to Bayport. Aunt Gertrude went into a frenzy when she heard about Topnotch and their suspect. âMy stable is not only a haven for retired race horses,â she cried, âbut for stolen ones as well!â

âLetâs call Mr. Steve Benson, attorney for the estate,â Frank suggested to his father. âHe should be able to give us more information on Dodson.â

Frank dialed the number. It took only seconds to reach the lawyer in Maryland. Benson was shocked to hear about the missing stable manager. He stated that Fowler had worked several months for the previous owner before their aunt inherited the business.

âBut I only knew him by the name Fowler,â Benson added. âHe was the most competent of all the workers there. When I was placed in charge of the estate I made him temporary manager.â

âIs there anything else you can tell us about him?â Frank asked.

âOnly that he was interested in buying the stable when he learned it was for sale,â the lawyer said. âHowever, he was unable to raise the cash. Later he asked if I would help him sell a piece of land that he owned.â

âA piece of land?â Frank blurted. âWhere?â

âIn northern Vermont,â Benson replied. âHe showed me the exact spot on a road map. It consists of about twenty acres and a cabin. But I wasnât really interested in handling the matter.â

Frank quickly obtained a map of Vermont. He then asked the attorney to describe where Fowlerâs land was located. Benson stated that it was just west of Highway 15, twelve miles north of the town of Haversville.

After Frank had hung up, he said, âIâll bet Fowler-Dodson has gone to his cabin!â

âIt would be a perfect place to hide out with Topnotch,â Joe agreed. âBut wouldnât he be taking a big chance? After all, he told Mr. Benson where his land was located.â

âDodson might be hoping the attorney forgot about it, or wouldnât think it important enough to mention,â Mr. Hardy said.

âHow about requesting the police up there to check the area?â Frank spoke up. âItâs been more than fourteen hours since we last saw Dodson. He could easily be in Vermont by now.â

Mr. Hardy telephoned Chief Collig again. Two hours passed before the Bayport officer called back.

âA couple of officers searched the cabin and some of the surrounding land,â he informed the detective. âAfraid youâre out of luck. They found nothing.â

âThanks, Chief,â Mr. Hardy replied. âBy the way, our suspect would have to transport Topnotch in a horse van. Would you send out an alarm to have all such vehiclesâspotted within a six- or seven-hundred-mile radiusâstopped and inspected? Although Iâm sure itâs too late for that now.â

âIâll do it, anyway,â the chief assured him.

âGuess weâve run into another blank wall,â Joe muttered.

âNot necessarily,â Frank commented. He snapped his fingers. âLetâs go to Vermont and take a look ourselves. Dodsonâs pretty clever. He certainly wouldnât keep Topnotch there at the cabin. Itâs possible heâs hiding somewhere nearby.â

âIâm with you,â his brother said.

âGo to it,â Mr. Hardy told them. âIâll have to stay behind and sit it out with Mr. Alden. Remember! Noon tomorrow is the deadline for him to pay the ransom.â

The boys alerted Jack Wayne for another flight the next morning. After an early breakfast, they drove to the airport and boarded the plane.

âFlight time should be approximately two and a half hours,â the pilot announced. âThe nearest field is about twenty miles from where you want to go.â

Jackâs estimated time to their destination proved to be correct. After landing, the Hardys arranged to rent a car.

âYou stick close to the phone here in operations,â Frank instructed Jack. âIf you donât hear from us in two hours, notify the police.â

âRoger,â Jack replied. âGood luck!â

Soon Frank and Joe were driving north on Highway 15. When they were twelve miles north of Haversville, they spotted a crude fence a few yards west of the road. On it was a large sign which read:

PRIVATE PROPERTY NO TRESPASSING

âThis must be Dodsonâs land,â Joe concluded.

Frank turned the car onto a narrow, dirt trail which jutted off the highway. After traveling a short distance he brought it to a stop.

âWeâd better continue on foot,â he advised.

The Hardys picked their way through an area of dense woods and brush. Soon they came to a small clearing.

âThereâs the cabin!â Joe declared, pointing to a dilapidated log structure directly ahead.

âLetâs watch it from here for a while,â Frank said. âThere might be someone inside.â

Half an hour went by. There was no sign of life, and the only sound was that of the wind rustling through the trees.

âI think itâs safe to go in,â Joe remarked impatiently.

âOkay. Letâs go!â

They skirted the clearing and approached the cabin from the rear. When they reached it, Frank cautiously peered through a window.

âThe place is empty except for a couple of pieces of furniture,â he told his brother.

The boys walked around to the front of the cabin and climbed two steps to the porch.

âCareful,â Frank warned. âThese planks are pretty creaky. Step lightly.â

The door of the cabin did not have a lock. The boys pushed it open and went inside. A wooden table stood in the middle of the floor with worn-out chairs set at each end. Suspended from the ceiling above the table was an old kerosene lamp.

Joe walked over to a cupboard mounted against the wall. He pulled open the door. âLook at this!â he exclaimed. âA supply of canned food!â

Frank inspected his brotherâs discovery. âThese cans look as if they havenât been here long. No dust on them.â

Suddenly the boys heard the voices of men in the distance.

âSomeoneâs coming!â Joe said excitedly. âSounds as if theyâre approaching from the woods behind the cabin.â

âLetâs get out of here!â Frank said.

The boys dashed through the door and across the clearing to the edge of the woods. They took cover in a clump of thick brush. A moment later three men appeared from around the corner of the cabin.

âThat tall guy is the one I trailed from the restaurant in Clayton,â Joe whispered.

âAnd we met the short one at the Southern Pines Stables when we went to see Dodson,â Frank hissed.

Neither of the Hardys recognized the third man, who remarked, âDodson would nail us to a wall if he knew we came to the cabin!â

âIâm hungry,â another said. âI canât wait till dark to get some of that canned food!â

The three men hurried into the log structure and slammed the door behind them.

âIâm going back and try to hear what theyâre saying,â Joe announced.

âItâs too risky in daylight,â his brother warned.

But Joe was already on his way. Frank watched him scoot across the clearing and carefully step up onto the porch of the cabin.

Suddenly there was a loud cracking sound. Frankâs pulse quickened. âSome of the planks are giving way underneath Joe!â he thought.

The next instant there was a crash as Joe fell through the porch floor up to his waist. Frank rushed to his aid. As he reached his brother, the three men spilled out of the cabin!

CHAPTER XIV

Daring Escape

THERE was a violent struggle. Frank lashed out at one of the men and sent him hurtling back into the cabin. The remaining two pounced on the dark-haired youth.

âRun for it!â Joe shouted as he frantically tried to free himself from between the planks.

One of Frankâs assailants caught him from behind with a headlock. The young detective flipped him high over his shoulder in judo fashion.

âHold it!â came an order. Frank suddenly found himself staring into the face of Dodson, who patted a rear pocket significantly.

âErâhi, Boss,â one of the men said nervously. âWe came to get some canned food and caught a couple of snoopers.â

âWhat did I tell you guys about coming here in daylight?â Dodson yelled. He glared at the Hardys. âHow did you know where to find me?â

âTrade secret,â Joe snapped as he finally worked himself free of the planks and rejoined his brother.

âThese kids probably told somebody they were coming here!â Dodson said to his cohorts. âWeâd better move the horse van to another hiding place.â

âBut what about the ransom money?â said one of the men. âKurt will be cominâ here after he picks it up.â

Dodson looked at his watch. âItâs early yet. Heâll still be in his room at the hotel in Clayton.â He turned to the short, wiry man the boys had met at the Southern Pines Stables. âBeaver! Get to a telephone and call Kurt. Tell him to go ahead as planned, then to drive to the bus terminal in Haversville. Weâll meet him there tonight.â

âOkay, Boss,â Beaver replied as he hurried off.

The boys were ordered to walk ahead of their captors.

âWhere are you taking us?â Frank demanded.

âYou two went to a lot of trouble to find Topnotch,â Dodson snarled. âIâm going to give you a chance to see him.â

The Hardys were marched along what appeared to be a very narrow trail through the woods. Actually they saw it was a wide, dirt road, cleverly covered with brush.

Soon the boys were ordered to halt. A huge mound of dried brush loomed in front of them. One of their captors pulled it aside.

âWhyâitâs a camouflage net,â Joe whispered to his brother.

âAnd itâs covering a horse van,â Frank answered in a low voice.

âShut up!â Dodson demanded. âGet inside!â

The boys walked up a ramp which formed the rear door of the van when closed. To the right in the back of the van was a small bedroom for the trainer. Ahead, another door with bars at the top opened into a stall. Inside was Topnotch who began to whinny at the disturbance.

Frank and Joe were roughly pushed into the van. A quick glimpse at the race horse revealed that his distinguishing white marks above the front hoofs had been dyed chestnut to match his coat.

âThis animal,â Dodson remarked with a laugh, âhas been living like a king. After all, he means fifty thousand dollars to me.â

âYou wonât get away with this!â Joe vowed.

âWhoâs going to stop me?â Dodson retorted. He then barked an order to his pals. âTie these wise guys up!â His henchmen shoved the boys inside the small room and uncoiled lengths of rope.

âNo use resisting,â Frank told Joe. He winked. âJust relax.â Joe nodded in response.

As they were being tied up, the boys took deep breaths and flexed their muscles hard. The men wound the ropes tightly around the boysâ bodies, then they left with Dodson. The rear door was slammed shut.

Instantly the Hardys exhaled and relaxed their muscles. The ropes went slack and the boys had little difficulty freeing themselves.

âThanks for reminding me to relax,â Joe said with a grin. âI had almost forgotten that old trick Dad taught us.â

âWeâre lucky Dodsonâs men donât know much about tying up prisoners,â Frank remarked.

A scraping sound outside told the boys that their captors were removing the camouflage net covering the van.

âTheyâre getting ready to move,â Frank said. âWe must get out of here fast!â

âLetâs make a break for it! Itâs our only chance.â

The boys dashed from the small room, but were dismayed to find the door of the van locked.

âThereâs no other exit!â Joe said frantically.

âI have an idea!â Frank whispered. âWeâll ride Topnotch out of here!â

âWhat! Through a locked door?â

âWeâll force Dodson and his men to open it!â

âHow?â

âBy raising such a racket that theyâll let down the door to investigate.â

The boys opened the door to the stall, patted the horse, who seemed to recognize them, then bridled him. Quickly they led Topnotch to within a few feet of the rear door.

âHey!â came the voice of one of their captors. âDo you hear Topnotch movinâ around?â

âProbably just restless,â Dodson replied. âHeâll calm down.â

Frank leaned close to Joe. âAll set?â he whispered.

His brother nodded, and the boys began pounding on the door with their fists.

âWhatâs that?â they heard a man shout. âItâs cominâ from inside the van.â

âMaybe the kids got loose!â Dodson declared. âWeâd better check. Quick! Open the door!â

The Hardys leaped onto Topnotch and flattened out on his back. As the ramp was pulled down, they nudged the race horse forward. He sprinted down the ramp, taking the men completely by surprise. Before they could recover, Topnotch had covered a hundred yards.

âTheyâre getting away!â one of the men yelled.

Suddenly Topnotch stumbled and the Hardys were thrown to the ground. They scrambled to their feet just in time to see Dodson take a small object from his pocket and throw it toward them.

âLooks like a tear-gas bomb!â Frank yelled.

Joe darted ahead and caught the object, then tossed it back at their captors. On contact with the ground, the bomb exploded and engulfed Dodson and his henchmen in a thick, white cloud of smoke.

The men wound the ropes tightly

As the choking gas began to drift away, the boys, holding their breaths, pounced on them and wrestled the men into the van. They shut and locked the door.

Joe glanced around. âWhereâs Topnotch?â

âHe ran off!â Frank said. âYou stay on guard here. Iâll go look for him.â

After a brief search Frank found the horse behind a clump of trees, entangled in heavy brush. He freed him and led the animal back to the van.

At that moment the Hardys were startled to hear their names called. âFrank! Joe! Where are you?â

âSounds like Jack Wayne,â Joe said. âHe must be at the cabin.â

Frank sprinted down the brush-covered trail. Reaching the clearing, he saw the pilot and two state troopers standing near the cabin.

âJack!â Frank shouted as he ran to greet them.

âAm I glad to see you!â Jack said with a sigh of relief. âI jumped the gun a bit. Didnât quite wait out a full two hours. Thought youâd call me long before that. I began to worry and notified the State Police.â

âGlad you did.â Frank told Jack and the officers what had happened, then led them to the van.

âYouâre under arrest!â one of the troopers announced as the boys pulled the door of the vehicle down. Dodson and his henchmen staggered out and were handcuffed.

âThere was a fourth man with them,â Joe put in. âHe went to make a call.â

âWhereâs the nearest telephone?â Frank asked the officers.

âThereâs a public booth about a mile and a half down the highway,â one of them replied.

Frank checked his watch. âLetâs drive in that direction,â he suggested. âBeaver was on foot. He should be on his way back by now.â

âWeâll use the patrol car,â one of the troopers said, and added, âIâll have to radio headquarters for more help.â

Leaving Jack and the other officer behind to guard the prisoners, the Hardys and their companion hurried to the highway. Soon they were cruising in the patrol car.

Minutes later, Joe pointed to a wiry figure trekking back along the highway. âThere he is! Thatâs Beaver!â

The officer brought the car to an abrupt halt and leaped out, with the boys close at his heels.

âWhatâwhatâs this?â Beaver shouted as he was placed under arrest. âHow did you kids escape?â

âSave your breath,â Joe snapped. âYouâll soon have enough talking to do.â

It was not long before more troopers arrived on the scene. Two grooms from a nearby stable were summoned to take charge of Topnotch until his owner could claim him.

Dodson and his cohorts were driven to Haversville Police Headquarters. There Frank telephoned Aldenâs plant.

âSorry,â said the executiveâs secretary, âbut Mr. Alden and Mr. Hardy left a few minutes ago on urgent business. I donât know when theyâll return.â

âTheyâre probably on their way to pay the ransom money,â Frank remarked as he hung up.

âThe guy named Kurt is in for a surprise when he arrives at the bus terminal tonight,â Joe commented with a grin. âHeâll have quite a reception party waiting for him.â

âYou can say that again,â Frank said. He then turned to their pilot. âJack, fly back to Bayport and keep trying to contact Dad and Mr. Alden. When you do, bring them here.â

âOkay.â

The Hardys interrogated the prisoners but without success. After an early dinner at a restaurant in town they returned to police headquarters. They were elated to find their father waiting for them.

âJust got here,â Mr. Hardy said. âHeard you boys cracked the horsenapping case. Good work.â

âThanks, Dad,â Frank answered. âWhereâs Mr. Alden? Didnât he come with you?â

âHe intended to. But just as we were leaving his office, he received word that Roger was involved in an automobile accident,â the detective explained. âJack went back to Bayport and will fly Mr. Alden here in the morning if Roger isnât seriously hurt.â

âWhat about the ransom?â Joe asked.

âMr. Alden decided to pay it,â his father replied. âHe received a call precisely at noon today and was instructed to leave the money in a public locker at the Clayton railroad station. I wanted to stick around and try to nab the pickup man, but Mr. Alden wouldnât hear of it. He was afraid of losing Topnotch if anything went wrong.â

The boys told him about Kurt.

âThis is a great piece of luck!â Mr. Hardy exclaimed.

Frank glanced at his watch. âIf Kurt picked up the money and departed from Clayton by one oâclock this afternoon, he should reach Haversville about ten or eleven oâclock tonight.â

As the hour neared, the three Hardys posted themselves across the street from the bus terminal. Several plainclothesmen were assigned to accompany them.

The time ticked by slowly. It was almost midnight before a car approached and parked in front of the terminal building. A burly man climbed out.

âThat could be our man,â Mr. Hardy whispered.

âTrouble is, we donât know what Kurt looks like,â Joe muttered.

Frank was struck with an idea. He stepped out of the shadows and nonchalantly walked toward their suspect. âHi, Kurt!â he said.

The man whirled. âHi! Erâwho are you?â he responded with a startled expression.

âYouâre under arrest!â the young detective declared.

The man tried to make a break for it, but Frank seized him. Plainclothesmen closed in from all sides.

âWhat is this?â their captive shouted. âI ainât done nothinâ.â

âWe know who you are!â Frank shot back

âWhereâs the ransom money?â Mr. Hardy demanded.

âWhat money?â Kurt sputtered.

âItâs probably in his car,â Joe put in. He quickly searched the vehicle and found a package stuffed underneath the front seat.

âThatâs it,â Mr. Hardy observed.

The prisoner was taken to police headquarters. There he was brought face to face with Dodson.

âGosh, Boss,â Kurt began, âI ...â

âShut up!â Dodson screamed. âIdiot! You walked straight into a trap!â

âBut nobody warned me! How was I supposed to know?â

âAs long as youâre in the mood for talking,â Frank spoke up, âsuppose you answer a few questions.â

âI told you before,â Dodson retorted, âyouâre not getting anything out of me.â

âIs there someone else in this with you?â Mr. Hardy inquired.

A smirk spread across Dodsonâs face. âWhy donât you ask Aldenâs son?â

CHAPTER XV

Plea for Help

âWHAT do mean by that remark?â Frank demanded.

âYou guys think youâre so smart,â Dodson snapped. âFigure it out for yourselves.â

After the prisoners were escorted to their cells, the Hardys went to a local hotel to spend the night. The next morning Mr. Alden and Jack Wayne arrived just as the boys and their father were finishing breakfast.

âYouâve done a terrific job,â Alden said. âAnd Iâm glad to know that Topnotch is all right.â

âWeâve recovered the ransom money too,â Joe announced.

âWhat!â Alden exclaimed. âThatâs incredible.â

After a pause Mr. Hardy inquired, âHowâs your son?â

âFine, thank you. It was just a minor car accident, and I was happy to hear it wasnât his fault. Fortunately Roger escaped injury and reported for work at the stable this morning.â

Frank said quietly, âWeâre sorry that your cousin is one of the thieves.â

Alden also expressed some remorse for Dodson. He hinted that he might drop the charges against him.

âBut you canât let him go free,â Mr. Hardy objected. âWeâve reason to suspect that your cousin is involved with someone who is trying to steal your experimental motor. He might turn out to be our only link.â

Alden finally agreed.

Then the detective said, âWeâre going to take another crack at questioning Dodson before we fly back to Bayport. Youâd better come to headquarters with us. The police will want a statement.â

âAll right.â Alden sighed. âBut please donât ask me to be at the interrogation. You understand. Anyway, I want to arrange to take Topnotch home today.â

When Dodson was grilled by the Hardys, he continued to be uncooperative.

âYou were the one who fired the smoke grenade into our fatherâs study, werenât you?â Frank said.

âI donât know what youâre talking about,â Dodson insisted.

âNo use denying it,â Joe interjected. âWe have evidence to prove that the grenade was fired from your rifle.â

The prisoner nervously gripped the arms of his chair. âYouâre lying!â he screamed.

âWhoâs trying to steal Mr. Aldenâs experimental motor?â Mr. Hardy demanded.

âI donât know anything about a motor!â Dodson shouted. He jumped to his feet. âI want to go back to my cell!â

Shortly he was ushered out of the room. The Hardys then questioned each of the other prisoners in turn. But they too refused to talk. Obviously Dodson had frightened the men into remaining silent.

After lunch Jack Wayne flew the Hardys back to Bayport. When they arrived, Frank suggested that they drive to the stable near Aldenâs plant and tell Roger about Dodsonâs remark.

âIâd like to see what his reaction will be,â Frank added.

âYou boys go ahead. I must get back to another case,â Mr. Hardy told them. âIâll take a taxi home.â

The boys hurried to the airport parking lot and climbed into their car. Soon they were at the stable confronting Roger with Dodsonâs insinuation.

âI barely know my fatherâs cousin,â the young man yelled. âHeâs crazy!â

âThen what reason would Dodson have for trying to involve you?â Frank asked.

Roger grew pale. âDonât ask me!â he retorted. âMaybe heâs trying to get back at my father through me.â

âThen youâve nothing to worry aboutâif youâre not involved,â Joe said.

âLeave me alone!â The young man nervously fumbled with a bucket he was carrying. âGet out of here! I have work to do!â

âOkay,â Frank replied. âBut donât forget this. When Dodson and his gang are put on trial, your name is likely to pop up again. If so, the prosecutor will have you subpoenaed.â

When the boys returned home, Chet Morton was waiting in the driveway with his bicycle.

âHi, fellows!â Their friend was bubbling with excitement. âLong time no see!â

âHello, Chet!â Frank said. âWhatâs with the bicycle? Car break down?â

âNo,â the plump youth answered. âRemember the rocket cycle I told you I was going to design? Well, this is it!â

Frank and Joe noticed a square canister attached underneath the seat of the bicycle. A long, funnel-shaped nozzle protruded from it.

âDonât tell us it works,â Joe said.

âI donât know yet,â Chet admitted. âI wanted to wait until you masterminds could be on hand to witness the supreme test.â

âForget it,â Frank advised. âThat thing looks dangerous.â

Chet shrugged off the warning. He leaped onto the seat of the bicycle and flicked a small toggle switch mounted on the handle bar. A crackling sound came from the canister. Then suddenly a long tongue of flame shot out from the nozzle. Chet was carried off with a roar. He maneuvered the bicycle through several wide circles as its speed rapidly increased.

âCut off the motor!â Joe cried anxiously.

âIâI canât!â their friend stammered.

In the next instant Chet steered on a straight course and vanished down the street in a trail of smoke. The Hardys jumped into their car and took off in pursuit.

âWhere did he go?â Joe said anxiously after they had traveled about half a mile.

âLook! Over there!â

Frank pointed to a bicycle, minus its rider, turned over on a spacious lawn. The wheels were still spinning.

âThereâs no sign of Chet,â Joe muttered worriedly.

âI see him!â Frank declared.

He led his brother to a thick hedge a short distance away. Chetâs legs were protruding from the top.

âAre you all right?â Joe yelled.

âYes, Iâm okay! Get me out of here!â

The boys pulled their chum free of the hedge. He was badly shaken by his experience, but other than a few scratches he had suffered no injuries.

âBetter stick to the old-fashioned way of propelling a bike,â Frank urged.

âGuess youâre right.â Chet sighed. âIt wasnât such a good idea, anyway.â

The Hardys drove their friend and his rocket bike to the Morton farm. Then they returned home in time to enjoy a delicious dinner. The meal was interrupted by the telephone. Frank answered it.

âThis is Roger,â the caller announced. He seemed frightened. âIâve got to see you right away. But I donât want to come to your home. Meet me at the municipal parking lot in Bayport.â

The boys quickly finished eating, then drove off to rendezvous with Aldenâs son. They found him seated in his car. At Rogerâs request the boys climbed into the rear seat.

âWhatâs this all about?â Frank demanded.

âYou must help me,â the young man pleaded.

âHelp you?â Joe snapped. âWhy should we?â

âIâm in terrible trouble,â Roger said shakily. âI was in on the theft of Topnotch. But I didnât know the horse was to be held for ransom.â

âThen why did you get involved?â Frank asked.

âI wanted revenge for the way my father has been treating me.â

âHow did you get mixed up with Dodson?â Joe questioned.

Roger stated that he met his fatherâs cousin one night in Clayton. âI realize now that it was not a chance meeting. He must have followed me there after work. Said heâd heard I wasnât on friendly terms with my father. I never thought to ask him how he knew that.â

âHm! Interesting,â Frank muttered.

âDodson then told me that he also had a grudge against my father,â Roger continued, âand asked me if I would like to play a joke on him.â

âLike stealing Topnotch?â Joe interjected.

âYes. But Dodson promised that the horse would be returned in a few days. It wasnât until they attacked the groom the night we took Topnotch that I realized the theft was meant to be more than a joke.â

âWhy did you meet two of Dodsonâs henchmen in that restaurant in Clayton?â Frank inquired. âBy then you knew they were crooks.â

âI had to,â Roger replied. âDodson sent them to warn me not to talk; otherwise heâd see that I went to jail with them.â

âWhat made you change your mind?â Joe asked.

âWhen you told me Dodson had mentioned my name, I thought it over and decided to tell you what I know. I would have before, but I was afraid.â

âYou made a wise decision,â Frank assured him. âAnd if you continue to cooperate, weâll do everything in our power to see that you get a break.â

âWhat should I do now?â Roger asked.

âI suggest you tell your father everything youâve told us,â Frank advised. âYouâre going to need his help as well as ours.â

Roger thanked the Hardys and drove off.

âRogerâs completely changed,â Joe commented as he and his brother returned to their car.

âHeâs scared,â Frank said. âAnd itâs a good thing. Maybe this will teach him a lesson.â

When the boys arrived home, their father greeted them with alarming news.

âDodson has escaped!â he announced.

CHAPTER XVI

Dilemma

FRANK and Joe were startled by the news.

âI canât believe it!â Joe exclaimed.

âHow did he manage to get away?â Frank asked quickly.

âThatâs the most fantastic part of what I have to tell you,â Mr. Hardy replied.

He told his sons that Lieutenant Monroe of the Haversville police had telephoned. The officer had informed him that Dodson escaped while he and his men were being transferred to the county jail in Myles City.

âThe prisoners were sent in a patrol car,â Mr. Hardy continued. âWhen they were about halfway to their destination, the windshield suddenly crazed. The driver lost control, skidded off the road, and turned over in a ditch.â

âLeaping lizards!â Joe exclaimed. âThatâs exactly what caused Mr. Aldenâs race cars to crash!â

âThen what happened?â Frank asked.

âThe occupants were badly shaken up,â the detective replied. âBut one of the officers faintly recalls seeing two masked men run toward the patrol car. They pulled Dodson out and disappeared. Thatâs all he remembers.â

âWhat about the men with him?â Frank inquired.

âThey were left behind,â Mr. Hardy answered.

âThatâs strange,â Joe muttered. âI wonder why.â

âI donât know,â their father admitted. âBut I suggest we fly to Myles City tomorrow and have another talk with Dodsonâs pals.â

At that moment Aunt Gertrude entered the room and began one of her tirades.

âHorsenappers! Ransom money! Itâs all too horrible to imagine,â she sputtered. âAnd to think those criminals were connected with that awful stable I inherited.â

âItâs not really as bad as all that,â Mrs. Hardy commented in a soft voice. âHorses are wonderful animals. Think how pleasant it must be for them to have a lovely place in which to retire.â

âFiddlesticks!â Aunt Gertrude retorted. âIâll have no part of it.â She glanced at Mr. Hardy. âAre you sure Mr. Benson is doing his best to sell the stable?â

âYes, he is,â the detective assured her. âYouâll probably be hearing from him any day now.â

âI certainly hope so,â his sister said. âThe next thing you know, theyâll be setting up public ticket booths and holding races in the paddock.â

The others smiled, then Frank changed the subject.

Early the next morning Jack Wayne and the Hardys were streaking down the runway on take-off at the Bayport field. Less than three hours later, the boys and their father were at the county jail in Myles City. Lieutenant Monroe was there to greet them.

âWeâve checked on the prisoners,â he said. âThey all have police records a mile long.â

âWeâd like to question them one at a time,â Mr. Hardy requested.

âOkay,â the lieutenant replied. âWe can use the chief guardâs office.â

Beaver was the only one among the three prisoners willing to talk. âDodsonâs left us holding the bag!â he growled. âThat rat wonât get away with this. Whatchaâ want to know?â

âWhen did you first meet Dodson?â Mr. Hardy asked.

âA couple of months ago in Maryland,â Beaver answered. âI was on the lam at the time and came across the stable he was managinâ. He was lookinâ for workers and offered me a job. I took it âcause I thought it would be a good place to lay low for a while.â

âWas it his idea to steal Topnotch?â Frank questioned.

âYes,â the prisoner admitted. âI got to be on friendly terms with Dodson. Told âim I had a police record. He said not to worry about it. Later he asked me if I would help his men steal a race horse, and get a couple oâ my friends to come in on the deal. Needinâ money, I jumped at the chance.â

âDo you know if he was involved in any other shady activities?â Joe asked.

âNot that I know of,â Beaver replied. âBut he was away from the stable two and three days at a stretch sometimes. Maybe he was up to somethinâ that he never told me about.â

âThink hard,â Mr. Hardy urged. âDid Dodson ever mention anything about experimental race cars or motors?â

âNot to me he didnât,â the prisoner answered.

When the interview was over, the boys and their father discussed the information.

âI believe he was telling the truth,â Frank commented.

âSo do I,â Mr. Hardy agreed. âAnd it explains why Beaver and the other two prisoners were left behind.â

âWhat do you mean?â Joe queried.

âIâm convinced that Dodson is part of a gang thatâs trying to steal Mr. Aldenâs experimental motor. The theft of Topnotch must have been his own private deal. As a result, the gang knew nothing about his horsenapping plans or the men who were helping him.â

âMakes sense,â Joe remarked. He thought for a moment. âBut how did the guys who helped him escape know he was being taken to Myles City?â

Frank turned to Lieutenant Monroe, who was seated nearby. âDid Dodson have any visitors, or make any phone calls from Haversville?â he asked.

âHe didnât have any visitors,â the officer told him, âbut he was permitted to make a call. When I informed him that we were taking him to Myles City, he demanded that he be allowed to contact his lawyer. I dialed the number for him.â

âDid you check the number?â Frank asked.

âNo,â the lieutenant replied. âBut I have a record of it back at headquarters. Iâll call the desk sergeant and have him check it immediately.â

Monroe picked up the phone. Twenty minutes went by before he obtained the information. âItâs an unlisted number in Clayton,â he said, âregistered in the name of Barto Sigor.â

âBarto!â Joe exclaimed. âMr. Aldenâs chief sheet-metal worker!â

Mr. Hardy jumped to his feet. âThereâs no time to lose!â he told his sons. âWeâre flying back to Bayport immediately!â

Shortly Jack Wayne and his passengers were airborne. When they reached their destination, the Hardys drove at once to Aldenâs plant. They found the executive in his office. He was greatly upset.

âWhatâs wrong?â Frank asked.

âBarto drove off in my experimental car!â Alden declared.

âWhen?â

âA few minutes ago! Iâve already notified the police.â

âHave you any idea which way he went?â Joe asked.

âNo.â

âYour car has a bright silver finish and a distinctive shape,â Frank commented. âWe should be able to spot it from the air.â

âGood idea!â Mr. Hardy said. âYou boys go aloft. Iâll stay here with Mr. Alden in case the police come up with anything.â

Frank rushed to the phone and dialed the number of Jack Wayneâs office at the Bayport field. Luckily he caught the pilot just as he was about to go home.

âSorry to ask you to go up again,â he said. âYouâve been doing so much flying the past couple of days youâre likely to sprout wings. But this is an emergency!â

âI donât mind,â the pilot assured him.

Frank glanced at Alden. âIs it okay if Jack lands the plane on your private drag strip?â he asked. âItâll save time.â

âBy all means,â the executive said.

Soon the boys and their pilot were cruising high above the plant.

âWhere do we start searching?â Joe inquired.

âMy guess is that Barto will stick to the back roads,â Frank explained. âThere are lots of them to the west.â

Jack maneuvered the sleek aircraft to a westerly direction. Frank and Joe scanned the terrain below. Thin ribbons of secluded roads cut across the hills and through the heavy forests.

âIâll climb a bit higher so you can take in more area,â the pilot said as he advanced the throttle.

More minutes passed. Then suddenly Joe pointed down toward a bright speck moving along one of the narrow roads. âLook!â he cried. âThat might be the car!â

âIâll go down on the deck and make a head-on pass,â Jack announced.

Descending to almost ground level, the pilot headed toward the oncoming vehicle. The tall trees that flanked the road seemed just inches away from the wing tips.

âItâs Mr. Aldenâs race car all right!â Frank observed. âBarto is pulling it off to the side.â

The plane swept by the vehicle at high speed. Then Jack pulled up into a climbing turn and came around for a second pass. As he did this, Frank saw a man run out onto the road. âMust be Barto!â he shouted.

As Jack flew closer, the boys noticed that the man was aiming a long, cylindrical object at them.

âBe careful!â Frank warned the pilot. âIt might be a weapon of some kind!â

In the next instant the windows of the plane crazed completely. The occupants were unable to see through the milky whiteness.

âWeâre flying blind!â Jack cried as he hauled back on the control wheel and soared skyward.

âHow can we land?â Frank asked tensely.

CHAPTER XVII

Emergency Landing

THE Hardys sat frozen in their seats. They heard the loud, thudding sound of the treetops whipping against the underside of the wings.

âI veered off course slightly!â Jack cried. âWe just managed to clear the trees!â

Seconds later a large, dark shadow flashed over the top of the planeâs canopy. This was followed by a severe buffeting that rocked the craft violently.

âWhat was that?â Joe shouted.

âWe almost collided with another plane!â the pilot declared nervously. âI must contact air traffic control. Theyâll have to handle us just as if we were flying in bad weather!â

Jack switched the radio transceiver to emergency frequency. âMayday! Mayday! Mayday!â he declared. âBayport Center! Do you read me?â

There was an immediate reply as the radioâs loudspeaker crackled to life. âThis is Bayport Center!â came a voice. âAircraft calling Mayday! Give position, altitude, and identification!â

âThis is Skyhawk One-One-Eight-Howe-Boscoe!â the pilot responded. âNow inbound on the two-eight-four-degree radial of Bayport Omni, approximately forty miles from the station! Present altitude, three thousand!â He then explained their predicament.

âRoger, Eight-Howe-Boscoe!â the air traffic operator replied. âMaintain present heading and altitude! Will advise when we have radar contact!â

It was several minutes before the air traffic controller informed Jack that the plane had been identified on the radar screens. He was also told that his craft would be brought down for a landing by means of a Ground Approach. Frank and Joe knew this meant radar operators would detect their aircraftâs heading, descent, and distance from a landing runway. Jack Wayne would be literally âtalked down.â

The boys watched in admiration as he skillfully maneuvered the plane. When finally advised by the controller that he had just crossed the threshold of the runway, Jack chopped the power and settled to the ground.

âWhew!â Joe sighed, mopping his forehead. âI donât want to go through that again. For a while it was like driving in heavy traffic with your eyes shut.â

Jack brought the plane to a stop. âWeâll wait here until a tractor arrives to tow us back to the hangar.â

After this was done, the Hardys and their pilot examined the windows of the plane curiously.

âIâve never seen anything like it,â Joe declared.

âIt looks as if something had upset the molecular structure of the material in the windows,â Jack said.

âWhatever caused the crazing,â Frank concluded, âmust have had something to do with that gadget Barto was aiming at us.â

âLetâs search his apartment in Clayton,â Joe suggested. âMaybe weâll find a clue.â

âJust what I had in mind,â Frank said. âIâll call Dad at Mr. Aldenâs office and ask if he can arrange to get a search warrant.â

âI almost forgot,â Joe interjected. âOur car is at the plant.â

âUse mine,â Jack said, tossing a set of keys to the boys. âIâll stay here and see about getting the windows replaced.â

The boys hurried off to meet their father at Aldenâs office.

âThe warrantâs all set,â Mr. Hardy said. âClayton Police Station is sending a man to meet us at Bartoâs apartment.â

They were greeted by a jolly, sturdily built policeman. âI got a master key from the superintendent,â he informed them. âMakes it easier.â

The Hardys were not surprised by what they saw when entering the apartment. A chest of drawers had been emptied of its contents and the closets were bare. The general untidiness of the rooms indicated that the tenant had left in a hurry.

âBarto didnât waste any time getting out of here,â Joe commented.

âDodsonâs call from Haversville obviously scared him away,â Frank concluded. âHe knew the police might check his number.â

âThis proves one thing,â Mr. Hardy put in. âBarto must be in with the gang thatâs after Aldenâs motor. In fact, he might even be the leader.â

Frank discovered a single fingerprint on the telephone. He lifted the print with his special tape and placed it in a celluloid container. âMust be Bartoâs,â he remarked. âBut Iâll ask Chief Collig to check it just to be sure.â

Meanwhile, Joe was rummaging through the wastebasket. He pulled out a crumpled, typewritten letter and two sheets of carbon paper. âIâve found something,â he called to his brother and father. They examined the letter together. It read: Dear Barto: Iâm sorry to hear that your brother had trouble with his employer and moved on. Perhaps the strain of his labors was too much for him.

I wish you could visit me. Iâm still operating my old mansion as a restaurant. One night I had forty customers. They came from miles around. However, I have competition about two miles north of my place. It is called the Claymore. Tonight I intend to go there to see how well they are doing. It is located just off the main highway. I must go now, since it is getting late and I always make a point of retiring by twelve.

Write soon.

Your friend,
Eric

âI wonder who Eric is,â Joe mused.

âToo bad we donât have the envelope the letter came in,â Mr. Hardy said. âIt would tell us where it was mailed.â

âWhatâs written looks innocent enough,â Frank observed. âJust the same, I want to examine it more carefully, and for luck Iâll take these two sheets of carbon paper.â

A further search of the rooms revealed nothing more. The Hardys thanked the Clayton policeman who had been assigned to accompany them and returned to Bayport. Frank stopped to give Chief Collig the fingerprint he had lifted from Bartoâs phone.

âIâll check it right away,â the officer said.

âThanks,â Frank responded. âIâll be at home. Please call me there.â

The boys and their father arrived home to find Aunt Gertrude in a jovial mood. âI have wonderful news!â she exclaimed. âMr. Benson telephoned. Heâs found a buyer. My stable is as good as sold.â

âGlad to hear it,â Mr. Hardy told her. âThat should put your mind at rest.â

âIndeed it will,â Aunt Gertrude agreed. âBut I hope the new owner is an expert in caring for horses. I would dislike the thought of those poor animals being neglected.â

âDo I detect a change of heart?â Joe asked with a grin. âHow come youâre so fond of horses all of a sudden?â

âI always have been,â Aunt Gertrude defended herself. âI just donât think they should be raced around a silly track for peopleâs amusement.â

Joe said, his eyes twinkling, âSomeday Iâm going to take you to a race!â

After supper the boys went to their crime lab and examined the letter they had found in Bartoâs apartment.

âDo you think it contains some kind of a code message?â Joe asked his brother.

âNot any more than the first letter I found in Bartoâs wastebasket the day I took his fingerprints from the doorknob,â Frank replied. âWhat about the sheets of carbon paper?â

âHavenât had a chance to examine them carefully yet,â Joe said. âSo far, it looks quite ordinary.â

At that moment Chet Morton entered the lab. âHi, masterminds,â he greeted the Hardys. âGot a few minutes to talk?â

âWe always have time for you,â Frank assured his friend with a smile. âWhatâs on your mind?â

âItâs about my rocket cycle,â Chet announced.

âOh, no!â Joe exclaimed. âI thought you gave that up as a bad idea.â

âI intended to,â Chet replied. âBut then I had a brainstorm.â

Frank winked at his brother. âThis ought to be good,â he remarked.

âOkay!â Chet protested. âIf you donât want to hear about my invention, just say so.â

âIâm sorry,â Frank said. âGo ahead.â

The chubby youth took a rolled sheet of paper from his hip pocket and spread it out across the table. On it was the rough sketch of a bicycle. âSee these tubes underneath the seat?â he -began.

âYes,â Joe told him. âHow could we forget? Theyâre your rockets.â

âWrong!â Chet declared with a flourish of his hand. âWhat you see are jet engines. And I wonât even have to build them myself. The hobby shop sells these units for model planes and boats. About four of them will produce enough thrust to propel my bike.â

âIf you insist on going ahead with the project,â Frank warned, âjust make sure that there are plenty of hedges around for you to fall into.â

âStow the comedy,â Chet retorted. âThe bike wonât run away with me again. Since the jets are operated with liquid fuel, Iâll be able to control the power.â

âWhen do you plan to unveil this great invention of yours?â Joe inquired skeptically.

âIn a couple of days,â Chet announced proudly.

âThis calls for a celebration,â Frank said. âAunt Gertrude baked an apple pie today. What say we go to the kitchen and have some?â

âLead me to it!â their friend exclaimed.

As the boys were being served, Chief Collig telephoned. âI just got the results on the fingerprint you gave me,â he said to Frank.

âI assume itâs Bartoâs,â Frank commented.

âNo,â the chief replied. âThe print is from his brother Vilno!â

CHAPTER XVIII

Night Chase

âTHATâS incredible!â Frank declared.

He and Joe rushed to their fatherâs study to tell him the news.

âThen Vilno was in his brotherâs apartment,â Mr. Hardy concluded. âBut why?â

âTo help Barto steal the experimental car,â Joe suggested.

âIf so,â Frank argued, âwhy wasnât Vilno with his brother when we spotted the car from the air?â

âMaybe they decided to go their separate ways after the theft,â Mr. Hardy said.

Frank frowned. âI wonder,â he muttered, âif Vilno has been posing as his brother all the time.â

âImpossible!â Joe said. âThose were Bartoâs fingerprints you lifted off the doorknob the day you followed him to his apartment. And donât forget, Vilno is not a sheet-metal worker. How could he do his brotherâs job at the plant?â

âGuess youâre right,â Frank finally agreed. âBut itâs an interesting theory.â

Mr. Hardy rubbed his chin dubiously. âIâm going to try getting more background on those two,â he said. âIt may lead up a blind alley. Yet I might discover some useful information.â

Their discussion was interrupted by a telephone call from Alden.

âThe police have retrieved my experimental car,â the executive told Mr. Hardy. âUnfortunately Barto got away.â

âWhat happened?â the detective asked.

Alden explained that a state trooper, who was patrolling the road indicated by the boys, had spotted the car traveling at great speed. He gave chase, but found that his motorcycle was not fast enough to close the gap.

âThen Barto blew a tire and spun out of control,â Alden continued. âBy the time the officer reached the spot, Barto was gone.â

âWas the car damaged?â Mr. Hardy queried.

âA little,â Alden answered. âBut nothing that canât be repaired in a few hours. In fact, I had considered entering it in a road race thatâs scheduled near here a couple of days from now. However, I donât think I will.â

After hanging up, the detective told his sons what Alden had said.

âI wonder where Barto was taking the car,â Joe mused.

âYour guess is as good as mine,â Mr. Hardy admitted.

Frank thought for a moment. âI have an idea,â he said finally. âLetâs ask Mr. Alden to enter his car in the road race. Then the night before the event Joe and I will inspect the route. We might spot one of those signposts.â

âItâs worth a try,â their father agreed.

The following morning Frank telephoned Alden and told him his plan.

âIâll do anything to help clear up the mystery,â Alden stated. He agreed to the plan, then described the route of the race.

After Frank put down the phone, Joe said, âI hope you donât plan on our using bicycles like the last time. If you do, Iâm going to ask Chet to install a couple of his jet engines on mine.â

Frank grinned. âWeâll use our car.â

âBut if there are members of the gang around, theyâll hear us coming,â Joe objected.

âSo far, the signposts have been set precisely beyond a sharp curve in the road. Thereâll be a full moon. We can cruise along with our lights out, and every time we come to a curve weâll stop and inspect it on foot.â

It was clear and cool the night before the event. The boys waited until midnight before starting out for the race site, which was situated a few miles west of Clayton. When they arrived, Frank turned out the headlights and drove slowly along the route described by Alden.

âMaybe weâre too early,â Joe warned. âIf the gang does intend putting up a signpost, we might finish our search before they get here.â

âWeâll keep patrolling the road till dawn,â Frank said. âIf they havenât set one up already, theyâll have to do it before daylight.â

The boys stared into the darkness. As they approached the first sharp bend in the road, Frank stopped the car. He and his brother edged their way around it on foot.

âNothing there,â Joe observed.

The Hardys returned to the car and continued on. They had almost covered the entire route when another sharp bend appeared ahead of them. They climbed out of the vehicle and walked forward.

âHold it!â Joe ordered in a low voice. âDo you hear something?â

Frank listened, then nodded. âSounds like several men mumbling to one another,â he whispered.

Crouching low, the boys cautiously worked their way around the bend. Then suddenly the Hardys came to a stop. The shadowy images of five men could be seen standing near a pickup truck a short distance down the road. A signpost stood nearby.

âRotten luck,â one of the men growled in a hushed voice. âThis generator we brought doesnât work.â

âWe shouldâve checked it out at the lab,â another man added.

âI know those voices,â Frank hissed. âItâs Dodson and Barto!â

âI wonder if Vilno is with them,â Joe whispered.

A couple of men lifted a heavy object onto the back of the truck.

âSlade! You and Tadlow go back and get another generator,â Barto ordered. âBut be quick about it. Everything has to be set up before it gets light.â

Two men leaped into the truck and started off. The driver executed a U-turn and headed in the direction of the Hardys.

Frank pointed to a clump of brush a few feet away. âTake cover!â

The boys managed to conceal themselves just before the truck flashed by.

âTheyâre bound to spot our car!â Joe said anxiously.

A moment later he and Frank were panic-stricken to hear the truck screech to a halt. Soon one of its occupants came running back to rejoin his companions.

âBarto!â the man exclaimed. âThereâs a car parked beyond the bend. It wasnât there before!â

âMaybe itâs the police!â Dodson sputtered.

âI donât think so,â Barto argued. âThey wouldâve driven up and asked us what weâre doing here.â He turned to his pals. âSpread out and start searching the area. There must be snoopers around.â

The men took out flashlights and began walking down the road toward the Hardys.

âWhatâll we do?â Joe said.

âOur only chance is to make a break for it,â Frank decided. âHead for the car. Thereâll be only one man to get past.â

The boys leaped to their feet and sprinted down the road as fast as they could.

âLook!â Barto yelled as he directed his beam of light toward the fleeing youths. âThere go a couple of guys!â

âItâs those Hardy kids!â Dodson shouted. âDonât let them get away!â

As Frank and Joe rounded the bend, they saw the driver of the truck standing beside their car. Joe crouched low, shot forward, and buried his right shoulder into the manâs midriff. The fellow went crashing to the ground.

Frank leaped behind the steering wheel of the car and started the engine. Joe climbed in beside him just as Barto and his friends bore down on the boys.

âStop them!â Dodson yelled.

After making a quick U-turn, the boys sped along the road and away from their pursuers. Joe peered out the rear window. âTheyâre coming after us in the truck!â

Frank gave the convertible more power. âAre they gaining on us?â

âNo!â Joe answered. âBut weâre not losing them either!â

After rounding another sharp bend in the road, Frank noticed a trail ahead which struck off to the right and into a wooded area. âHang on!â he cried. âIâm going to try something!â

Swerving sharply, Frank turned onto the trail. After they had traveled a short distance, he switched off the engine and lights. A moment later their pursuers raced past and continued down the road.

âYour maneuver worked!â Joe said with a grin.

âWeâre not out of this yet,â Frank warned. âBarto and his men are sure to figure out what happened. Weâll get back on the road and drive in the opposite direction.â

He restarted the engine and rolled only a few feet when he brought the vehicle to a stop.

âWhatâs wrong?â Joe queried.

âIâm afraid we have a flat!â

The boys climbed out of the car and were dismayed to see that the left front tire had been punctured by a sharp rock.

âWhat a time to have this happen!â Joe muttered.

The Hardys made a break for it!

At that instant they heard the sound of a vehicle approaching in the distance.

âIt must be Barto and the others!â Joe concluded.

âQuick! Letâs hide!â

âWhere?â

Frank glanced around. âWeâll climb a tree. That one over there should be the easiest. Get going! Iâll follow you!â

Soon the Hardys were pulling themselves up through the branches, high above the ground. A thick mass of leaves provided excellent cover. There was one small clear spot which permitted them to view the road.

âWe made it just in time,â Joe said. âThereâs the pickup truck. Barto and his men are turning in here!â

The boysâ pulses quickened as they watched the truck come to a halt immediately behind their car.

âI told you those kids mustâve turned in here after we didnât see them on the road ahead!â Dodson declared. âGood trick. Lucky I remembered our passing this trail.â

âBut where are they?â Barto growled. He examined the damaged tire. âI see they have a flat. Why didnât they try to fix it?â

âProbably heard us coming and ran off,â Dodson replied. âJust the same, letâs take a look around.â

Frank and Joe were almost afraid to breathe as they watched their pursuers take out flashlights and search the area. At one point, a beam of light was directed toward the place in which the boys were hiding.

âThat was close,â Frank thought as the beam was finally turned downward.

âWeâd better not waste any more time here!â Barto shouted. âThose snoopers may be on their way to call the police!â

âTheyâve ruined everything,â Dodson snarled. âWeâll have to forget about using the signpost on Aldenâs car during the race. Letâs pick it up and get out of here.â

One of the men walked to the rear of the Hardysâ car with a sharp-pointed tool. He proceeded to punch several holes into the fuel tank. Gasoline began to stream from it. âThatâll stop âem from usinâ this in case they come back.â

Barto and his henchmen climbed into the truck and drove off. The Hardys waited a few minutes before leaving their hiding place.

âHere we are in the middle of nowhere without transportation,â Joe said angrily.

âWonât help to complain about it.â Frank sighed. âMust be five or six miles to the nearest telephone. Letâs start walking.â

They began trekking along the road. It had been daylight for more than an hour when they saw a sedan approaching.

âOh-oh,â Joe remarked. âI hope none of Bartoâs men are in it.â

As the car came to a stop, the boys were elated to see Alden behind the wheel and their father seated beside him.

âAm I glad to see you two!â Mr. Hardy called out. âI became worried when I didnât hear from you. I decided to look for you and asked Mr. Alden to come along.â He peered at his sons curiously. âWhy are you walking? Whereâs your car?â

The boys climbed into the rear seat of Aldenâs car and told the men what had happened. Then they drove to the spot where they had seen the signpost.

âThis is where it was,â Frank announced, pointing to a small hole on the shoulder of the road.

âThe gang made certain that they didnât leave any clues behind,â Mr. Hardy observed.

âYou boys have saved my experimental car from being wrecked,â Alden interjected.

âYou must be tired,â Mr. Hardy said to his sons.

âI insist you come to my home for breakfast and a few hoursâ sleep,â Alden added.

The young detectives readily agreed. They rested until midafternoon, then returned to Aldenâs office. They had been there only a few minutes when the phone rang. Alden picked up the receiver. He turned pale as he listened to what his caller had to say.

âWhatâs the matter?â Mr. Hardy asked after his client hung up.

âThatâthat was Bartoâs brother Vilno!â Alden stammered. âHe has Roger! He said unless I give him my experimental motor, heâll harm my son. Heâs calling again in two hours for my answer.â

CHAPTER XIX

Breaking the Code

THE Hardys were shocked by the news.

Alden was almost at the point of collapse. âIf Vilno and his gang want my motor that badly, Iâll give it to them.â

The three detectives were angry. Mr. Hardy exclaimed, âIâd like to get my hands on those scoundrels! Theyâll stop at nothing!â

âIf only we had a lead to where their hideout is,â Joe put in.

Frank frowned. âMaybe the lead is right in our files at home.â

âWhat do you mean?â Joe asked.

âMaybe the letters we found in Bartoâs apartment do contain a code after all,â Frank answered.

Mr. Hardy nodded. âWhy donât you boys go back to Bayport and work on that angle?â He handed them a set of keys. âTake my car. Itâs in the plantâs parking lot. Iâll stay here and be on hand when Vilno calls back.â

âMeanwhile,â Alden told the boys, âIâll send one of my tow trucks to pick up your car.â

Frank and Joe hurried home, took Bartoâs letters from the file, then went to their crime lab to study them.

After an hour had passed, Joe sighed. âWeâre no closer to discovering a key than we were the last time we examined the letters.â

âLooks hopeless,â Frank agreed. âBut letâs keep at it a bit longer.â

Shrugging, Joe turned his attention to the sheets of carbon paper found in Bartoâs apartment. He scrutinized them carefully and thought they looked a bit different from the usual carbon paper. Suspicious, Joe sandwiched a sheet between two sheets of white paper, picked up a pencil, and began scribbling on the upper one.

Suddenly he sat bolt upright. âThis is odd! The carbon doesnât produce a copy except in a few isolated spots.â

Frank jumped to his feet. âJoe! You may have discovered the key to the code!â

âI hope so. Fortunately our typewriter has pica type like Bartoâs machine. Iâll type an exact copy of the first of his letters,â Joe said. âIf our hunch is correct ...â His words trailed off as he inserted two clean sheets into the typewriter. Then he began tapping out the words.

Dear Eric:

Forgive me for taking so long to write you, but Iâve been so exhausted from work the last few days that I didnât feel I could write a coherent sentence. How I wish I had the stamina of two hard-working boys who have taken summer jobs at the plant. Any family would be proud to have sons like that.

As I already told you, my brother has left the Alden company ...

When Joe finished typing the letter, he pulled out the sheets and quickly examined the carbon copy.

âThatâs it! Weâve broken the code!â he exclaimed. âTrick carbon paper!â

Joe showed Frank the copy. âNotice that the carbon has transferred only certain words and portions of words onto the copy sheet. First we have the word âhard.â Next, the âyâ and âsâ from the word âboys.â â

âSpelling out âHardysâ!â Frank declared.

âAnd the next word is âsons,â and so on.â

The boys observed that the complete message read:

Hardys, sons of detective, here. Iâm sure theyâre investigating.

Tingling with excitement, Frank handed his brother the second of Bartoâs letters and the other sheet of carbon paper. âQuick! Make a copy of this!â

Joe repeated the procedure. The carbon copy revealed the following message:

moved lab to old mansion forty miles north of Clayton on route twelve.

âIt must be the location of the gangâs hideout !â Frank exclaimed.

He rushed to the telephone and dialed Aldenâs private office number. There was no answer.

âItâs after office hours,â Joe said. âMr. Aldenâs secretary must have left. Why donât you try the companyâs main number?â

Following his brotherâs suggestion, Frank finally got a response from the plantâs chief watchman. âSorry, I canât help you,â the man told Frank. âMe and my men just came on duty. I havenât seen Mr. Alden or anyone else.â

Next, Frank tried the executiveâs home. Again there was no answer.

âI wonder where Dad and Mr. Alden are,â Frank muttered.

âMaybe they went to meet Vilno.â

âDad would have called us. I donât like this.â

âIf theyâre delivering the experimental motor to Vilno, he and his gang may try to make a getaway after they have it. Letâs go to their hideout.â

âOkay!â Frank agreed. âBut since Mother and Aunt Gertrude wonât get home from the theater till late Iâll ask Chet to stand by the phone here. He can tell Dad where we are if he should call.â

Twenty minutes later Chetâs ancient yellow car rumbled to a stop in front of the Hardy home. The boys noticed that their friend had his jet-propelled bicycle lashed to the rear bumper.

âIâm taking my bike to a secret spot early tomorrow morning,â Chet announced. âItâs ready for the supreme test.â

âLots of luck,â Frank said. âI hope the job weâre asking you to do isnât going to interfere with your plans.â

âNot at all,â the chubby youth replied grandly. âWhat is it you want me to tell your father if he calls?â

Frank handed him the message they had decoded revealing the location of the gangâs hideout.

âIâd rather be going with you,â Chet muttered, âinstead of having to sit at the telephone.â

âWe wish you could too,â Joe assured him. âBut your job is an important one. Weâll check with you later.â

It was already dusk when the Hardys drove off. Forty miles to the north of Clayton, Joe pointed to a dimly lighted building in the distance. âI think Iâve spotted the mansion! Itâs behind those trees over to the right.â

Frank brought the car to a stop near the foot of a long wooded driveway. He and his brother continued on foot. The house was situated quite a distance from the main road.

âI donât see anybody or signs of activity,â Joe whispered as they neared the building.

âJust the same, be careful. If this is Vilnoâs hideout, heâs sure to have one or more guards posted.â

The boys crept forward toward the front of the house, keeping in the darkness of the trees. Suddenly Joe grabbed his brotherâs arm. âLook!â he whispered. âThereâs a man up ahead, seated on that big rock. Heâs armed!â

âItâs a guard all right, Joe. Heâs Tadlow, one of the men we saw with Barto and Dodson at the sinister signpost!â

âThen weâre at the right place. Letâs nab him.â

âOkay.â

The Hardys stalked their quarry. When they were within armâs reach of the man, he jumped to his feet and whirled around to face them.

Quick as a flash Joe leaped and caught the man squarely on the jaw with a right uppercut. He tumbled to the ground, unconscious. Nearby lay his rifle, which Frank flung into a clump of brush.

The boys dragged the man to a slim tree, put his arms around the trunk, and tied his wrists together with a belt. The placing of a handkerchief gag completed the job.

Moving cautiously, the boys continued toward the mansion. They kept a sharp lookout for other guards, but there were none. When the Hardys reached their goal, they detected a humming sound.

âWhat do you think that is?â Joe hissed.

âOffhand, Iâd say itâs some kind of machine,â Frank answered. âSeems to be coming from the basement.â

The boys started to creep around the outside of the mansion. Soon they discovered a metal air vent in the foundation. Frank peered through it in amazement.

âSee anything?â Joe asked in a hushed voice.

âYes. Looks like a physics or electronics laboratory.â

Joe crouched just as three men came into Frankâs view. They were Vilno, Barto, and Dodson. The boys pressed their ears against the vent in an effort to hear what the men were saying.

âThis is a good setup here,â Barto remarked. âToo bad we have to leave it.â

âNow that we have the experimental motor,â Vilno put in, âthereâs no reason for us to stick around.â

âWhat about the prisoners?â Dodson inquired. âAlden and his son donât worry me, but that detective Hardy can be dangerous to us.â

Frank and Joe gasped. Their father had been captured together with Mr. Alden and Roger!

âForget it,â Vilno told Dodson. âWeâll be miles away before anyone finds Hardy.â

Frank turned to his brother. âWe must rescue them!â

âWe canât do it alone! There are probably more members of the gang inside.â

Suddenly the tall figure of a man loomed up behind the boys. âWho are you?â he demanded.

Frank and Joe leaped to defend themselves. A wild struggle followed. They crashed against the side of the house several times. Then Frank dealt the man a blow that sent him crumbling to the ground.

Suddenly the young detectives heard another, but louder, humming sound. In the next instant they were horror-stricken to find that they could not move.

âWhatâs happening?â Joe exclaimed.

The boys were frozen in their tracks. Some powerful, invisible force was holding them!

CHAPTER XX

Jet Action

âITâS THE Hardy kids!â Dodson shouted as he, Barto, and two other men arrived on the scene.

âDonât get too close to them,â Barto warned his pals, âor youâll get caught in the sonic trap yourselves. Tadlow! Go tell my brother to turn it off.â

Within a couple of minutes the boys were released from the mysterious force that had prevented them from moving. The aftereffects, however, caused Frank and Joe to fall to the ground exhausted. Dodson and the others pounced on them and tied the boysâ hands behind their backs.

âSo! How do you like our little sonic trap?â Barto sneered.

âSonic trap?â Frank said weakly.

âYes,â Barto replied. âItâs another of Vilnoâs inventions. A device which encloses objects of our choosing within a solid shell of hypersonic vibrations. Your father also had the honor of experiencing its effects.â

Frank and Joe were marched into the mansion, then down a flight of stairs leading to the basement. They were awed by what they saw. The area had been converted into a large laboratory, and was filled with various pieces of electronic equipment. In one corner of the room lay several signposts marked DANGER.

âWelcome! Welcome!â Vilno exclaimed with exaggerated politeness. âLooking for your father? Well, youâve come to the right place.â

âIf youâve harmed him,â Joe began, âor ...â

âHeâs perfectly fit,â Vilno interrupted, âand is in our storage room with Alden and his son. You shall join them shortly.â

For the first time the boys had an opportunity to see Vilno and Barto together. They were identical twins. Other than for a difference in dress, it was difficult to tell who was who.

âPerhaps our guests would like to see some of the things we invented,â Barto sneered.

âThat we invented? Youâre forgetting it was my genius alone that made our devices possible!â his twin said boastfully.

âHow did you manage to craze the windshields of Mr. Aldenâs race cars?â Frank interjected.

Vilno seemed pleased by the question. He led the Hardys to the signposts. âInside each of these is a hypersonic generator of my own design. I found that I could disturb the molecular arrangement in some materials with the waves it produces. They are what crazed the windshields of Aldenâs cars.â

âAnd the windows of our plane!â Joe said angrily.

âAh yes,â Vilno said. A sinister smile spread across his face. He walked to a table and picked up a long, cylindrical object. âYour plane was among the first objects on which I tried the portable version of the hypersonic generator.â

âThen it was you, and not Barto, who stole Mr. Aldenâs experimental car,â Frank remarked.

âPrecisely,â Vilno replied.

At that moment Barto began to roar with laughter. âThey still donât know,â he told his brother, âthat it was you who was working at the plant all the time, posing as me!â

âBut how could you carry on the deception?â Joe sputtered. âYouâre not a sheet-metal worker.â

âThatâs where youâre wrong,â Vilno shot back. âMy brother and I were both trained in sheet-metal work as youths. But I never claimed it as one of my skills. My ambition was to become a scientist.â

âWhy are we standing around here talking?â Dodson said impatiently. âThese snoopers might have told the police they were coming here!â

âThen where are they?â Vilno countered. âYou worry too much.â

âI donât care what you say!â Dodson retorted. âI ... â

âShut up!â Barto broke in. âWe shouldâve let you stay in jail for stealing Aldenâs race horse. Why did you do it? Arenât we paying you enough?â

âAnd your stupidity didnât end with the horse theft,â Vilno added with a touch of irritation. âYou made the mistake of telephoning me at my apartment from Haversville Police Headquarters. Idiotl I knew the Hardys were bound to check the number.â

Dodson grimaced but said, âYouâre not so smart. You started a fire in the experimental lab.â

Frank broke in. âVilno, you say you were posing as your brother all the time. Yet it was Bartoâs fingerprints I found on the doorknob of your apartment the day I followed you home from the plant.â

âQuite simple,â Vilno answered proudly. âBarto and I were dressed exactly alike and switched places in the lobby. It was he you saw enter the apartment.â

âBut how did you know you were going to be followed that day?â Joe asked quickly.

âYour taking summer jobs at the plant didnât fool us,â Barto put in. âWe knew you were probably investigating the Alden case. Vilno guessed that he would be a suspect, and that you would undoubtedly shadow him. So, each day, we wore similar clothes in the event we had to switch places. The plan paid off. You followed the wrong one on the street in Clayton. Vilno pretended a friend was a bum and shoved him away.â

âWeâve told them enough,â Vilno growled. âPut them in the storage room with the others.â

Dodson and two men marched Frank and Joe out of the laboratory and down a narrow passageway. They came to a stop in front of a heavy metal door. Dodson pulled it open.

âInside!â he ordered.

The boys entered a small, windowless room made of stone. Before the door was closed, they saw their father, Alden, and Roger.

âDad!â Joe exclaimed.

âI see you two also had some bad luck,â the detective said remorsefully.

The metal door clanged shut and the Hardys and their companions were in total darkness.

âWe were surprised to learn that you and Mr. Alden had been captured, Dad,â Frank remarked.

âI walked into Vilnoâs sonic trap,â Mr. Hardy explained.

âHow did you find the gangâs hideout?â Joe asked.

âAfter you left Mr. Aldenâs office, I went to Clayton Police Station in Mr. Aldenâs car to tell them about the situation, and to arrange for help in case we needed it. I planned to return to the plant in time for Vilnoâs telephone call. When I was driving back, I saw Mr. Alden go by me from the opposite direction in a truck.â

âSorry about that.â The executive sighed. âThis is how it happened, boys. Vilno called me again shortly after your father left. He told me heâd been watching the plant and saw Mr. Hardy drive off. Vilno was worried he was going to the police and demanded I deliver the experimental motor to him immediately. For Rogerâs sake, I had no choice.â

âWhat happened then?â Frank asked.

âVilno ordered me to bring the motor to the Bryant crossroads north of Clayton,â Mr. Alden replied. âThere, two of his men jumped into the truck with me and told me to drive on. We came here to the mansion.â

âI followed the truck,â Mr. Hardy interjected. âToo bad I didnât have my own car, or I would have contacted you boys by radio. And unfortunately I couldnât stop to use a telephone.â

âYou people wouldnât be in this mess if it wasnât for me,â Roger muttered.

Frank began to grope around their enclosure, hoping for a way of escape. His father said, âThe walls are solid, and you couldnât budge that metal door with a bulldozer.â

âThe room is completely sealed,â Mr. Alden added, âexcept for an air vent. Thank goodness for that.â

âAir vent,â Frank repeated, looking for it.

âItâs near the ceiling,â Mr. Hardy said. âBut if youâre thinking of an escape route, itâs too small for any of us to crawl through.â

âLet me try,â Joe urged. âIâve managed to squeeze through some pretty small spaces before.â

Mr. Hardy guided his sons to the rear wall of the room. âThe vent should be directly above this spot.â

Frank hoisted his brother onto his shoulders. Joe ran one hand along the upper portion of the wall. âIâve found it! The vent is covered with a metal grating.â There was a momentary pause. âI think I can pull it loose.â

Joe tugged the grating hard. Finally it broke free of the wall. âThe opening is small, but Iâm sure I can manage to get through. Boost me up higher.â

Frank grabbed his brotherâs feet with both hands and shoved him upward. An instant later Joe was gone.

âBe careful, son,â Mr. Hardy called.

But Joe was not free yet. He was in an air duct. His arms stretched out in front of him, Joe forced his way through the narrow passageway. Minutes seemed like hours. Finally he was elated to find that the vent led directly outside the mansion.

Another grating, however, barred his way. He grasped the bars with both hands and shoved with all his strength. The grating loosened and dropped outside to the ground.

After climbing out of the vent, Joe scanned his surroundings. Several yards away he saw Vilno and his henchmen preparing to depart in Aldenâs truck.

Stealthily, the young detective stalked toward the front door of the mansion. Luckily it was unlocked. He raced inside and ran down to the storage room to free his companions.

âQuick! Vilno and his men are getting ready to leave!â

The three Hardys and their friends rushed outside the mansion. They were crestfallen to see that the truck had already pulled away.

âWeâll never catch them!â Frank declared.

âLook!â Joe yelled. âWhatâs that glow?â

His companions were startled to see a bright ball of light approaching the truck head-on. Just as a collision seemed imminent, the vehicle veered off the lane. This was followed by a loud crunching sound.

âWhatâs that?â Alden shouted.

They detected a roar as the glow grew closer. Then it suddenly vanished. Seconds later Chet Morton coasted out of the darkness on his jet-propelled bicycle.

âHi, fellows! Am I glad to see you!â

âChet! What are you doing here?â Frank exclaimed.

âI began to worry when I didnât hear from you,â the chubby youth explained. âSo did your mother and aunt. I decided to see what was going on. My car ran out of gas about a mile from here, so I came the rest of the way on my jet bike.â His eyes widened. âBy the way, I almost ran into a truck! What happened to it?â

The Hardys hurried to the spot where they had seen the vehicle veer off the lane. They found it tightly wedged between two stout trees. Vilno and his pals were desperately trying to open the doors but without success.

Just then a State Police car arrived on the scene. One of the troopers got out. âDid any of you see a wild kid on a bicycle?â he questioned. âWe think it turned in here. Looked as if it was on fire.â

âIâm the one,â Chet admitted sheepishly.

âWhat were you trying to do?â the officer demanded. âYou went by us as if youâd been shot out of a cannon.â His attention was attracted by the disabled truck. âWhat happened here? Accident?â

Mr. Hardy stepped forward. âLet me explain,â he said.

After hearing the story, the officer radioed for additional men, then the troopers took Vilno and his henchmen into custody.

âWeâd have escaped if it hadnât been for that crazy friend of yours and his bicycle,â the gang leader growled.

âThatâs your hard luck!â Joe told him.

Mr. Hardy said, âWe know that specifications of Mr. Aldenâs motor were leaking out of the plant. How did you manage it?â

Vilnoâs egotism caused him to forget his predicament for a moment. âEasy! Aldenâs machinists worked from plans recorded on film slides. I just roamed around the plant and photographed the projected pictures with a spy camera in my wrist watch. Other components I committed to memory and put them down on paper later.â

Soon more troopers arrived. The prisoners were herded into patrol cars. The case of The Sinister Signpost was over. Frank and Joe always regretted such a moment. They were not restless for long, however, because the mystery of A Figure in Hiding soon came their way.

Before departing, one of the officers walked up to Chet. âI should give you a ticket for speeding,â he announced, winking at the Hardys.

âIâI wish you wouldnât,â Chet stammered, âIt wonât happen again.â

âWell, under the circumstances, I think I can overlook it this time.â The trooper sighed, trying not to grin. âAnyway, I wouldnât know how to describe your jet-propelled bike to the judge,â

âWe warned you about that invention of yours,â Joe whispered, nudging his chum, âLucky for us you didnât listen!â