THE MARK ON THE DOOR

IN their motorboat the Sleuth Frank and Joe Hardy search Barmet Bay for a dangerous stranger who has stolen a valuable boat. Suddenly, in the eerie fog, they spot the craft drifting aimlessly out to sea. What happens next starts the young detectives and their pal Chet Morton on an intriguing adventure that takes them to Mexico and into the comparatively unexplored desert and mountain regions of Baja California.

The search for the meaning behind a mysterious symbol that terrorizes the people of an entire village, a daring escape from a submarine, perilous encounters with a band of renegade Indians, an unusual smuggling operationâ€”all combine to make this one of the Hardysâ€™ most exciting cases.

Frank and Joe dangled precariously
above the rocky chasm

Copyright Â© 1995,1967,1961, 1934 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 : 978-1-101-07627-9

2008 Printing

http://us.penguingroup.com

CHAPTER I

The Attack

âLOOK! A periscope!â Joe Hardy shouted.

âAre you sure?â asked his brother Frank, who was at the wheel of their motorboat.

âYou bet. Look over there!â

The Hardys were skimming across Barmet Bay in the Sleuth, checking it out before going on a fishing trip to Maine with their father.

Frank spotted the thin, tapered metal mast to starboard, generating a tiny wake as it moved through the water.

âI see it now, Joe!â

âLetâs take a closer look!â his brother cried.

Frank turned the wheel and advanced the throttle as they sped toward the periscope, but suddenly it sank beneath the waves!

Frank looked disappointed, and cruised around in a tight circle. âIt must belong to the U.S. Navy.â

âMaybe not,â Joe replied.

The blond boy was seventeen, one year younger than dark-haired Frank. Both had learned from their detective father to be constantly on the alert.

A better instructor in police matters was nowhere to be found. Fenton Hardy, a former member of the New York City Police Department, was renowned as a super-sleuth.

Frank and Joe had become so preoccupied with the periscope that they failed to take notice of a speedboat approaching them from the rear. The craft made a close pass, then suddenly turned away so sharply that its stern skidded and struck the bow of the Sleuth. The boys hung on as sheets of water showered over them.

âWhat does that cowboy think heâs doing?â Joe sputtered.

Frank rammed the throttle ahead and raced off in pursuit of the other boat. The Sleuth gained at first, enough for the Hardys to glimpse the name Ira Q painted on the stern. But the pilot of the fleeing craft applied more power and pulled away.

âThat boat is too fast for us!â Joe shouted.

âI know,â his brother agreed. âBut I managed to get a good look at the guy behind the wheel. He looks Spanish. But the boatâs name isnât.â

âIra Q? Never heard of it,â Frank said. âMaybe itâs a transient.â

âPerhaps. Anyway, Iâm sure that speed demon is heading back to shore,â Joe replied. âLetâs go in and make some inquiries.â

âWeâd better telephone the Coast Guard station and tell about that periscope, too,â Frank added.

The boys arrived at their private boathouse and tied up the Sleuth. An examination showed that she had a dent in her side. Then Frank went to a telephone booth and dialed the Barmet Coast Guard Station.

A manâs voice crackled from the receiver. âCoast Guard. Lieutenant Parker speaking.â

Frank told him what he and Joe had seen.

âThank you for the information,â the lieutenant replied. âSince no sub is expected here, Iâll have one of our cutters start an immediate search!â

The respect and cooperation extended to the Hardys was typical of all who knew them. Frank and Joe often worked with their father on his cases, and their ability in solving baffling mysteries had won the youths an enviable reputation of their own.

After Frank had hung up, the boys made a reconnaissance of the piers and docks stretching along the shore of Barmet Bay.

Presently Joe grabbed his brotherâs arm. âI see the speedboat!â he said excitedly.

âWhere?â

âAt Sandy MacPhersonâs place!â

The boys ran to the dock of MacPhersonâs Boat Rental Service, where Sandy, an elderly Scot, seemed to be talking to himself.

âThe brigand!â he stormed. âHe bashed in the stern of me new boat! Iâve had the Ira Q but three days, and already itâs damaged! Heâll pay for this!â

âWho?â asked Frank.

âThat Mexican fellow!â

âWeâre after him, too,â Frank said. âHe damaged your boat when he ran into ours.â

âWhat!â MacPherson exclaimed. âHeâll no get away with this!â

âCalm down, Mr. MacPherson,â Joe pleaded. âYou say the fellow was Mexican?â

âYes,â the proprietor answered. âPancho Cardillo was the name he gave me. He seemed to know quite a bit about boats. So I paid no mind when he asked me to rent him the Ira Q.â

âDid he give you an address?â Frank asked.

âYes,â MacPherson said. âHeâs at the Hotel Bayport. Thatâs where he is.â

âThanks,â Frank said. âJoe and Iâll go there right away. This Cardillo fellow might suddenly get the idea to leave town.â

After learning that Cardillo had driven off in a car, the boys hastened to their own convertible, which they had left near the boathouse. Frank headed for downtown Bayport. He parked in front of the hotel, then the young detectives darted into the lobby and approached the desk clerk.

âMay we have Pancho Cardilloâs room number, please?â Frank asked.

âYou mean Senor Cardillo,â the clerk replied. âHe checked out just a few minutes ago. Paid his bill in pesos. Highly irregular. I had no alternative but to accept. Figuring out the exchange is always a nuisance.â

Frank interrupted the clerk. âWhat address did he list in your register?â

The man glanced at his card file. âTampico, Mexico,â he answered. âAnd thatâs all I can tell you. The gentleman paid his bill and hurried to a car that was waiting for him outside.â

âCan you give us a description of the car?â Frank prodded.

The clerk became irritated. âWhat do you fellows think I amâthe FBI?â

âWell, thanks anyway,â Frank said, and the boys hurried back to their own automobile.

Night had come on quickly, but Frank and Joe decided to make one more inquiry about Cardilloâs car. If they had a description, Police Chief Collig could issue a bulletin to pick him up.

âIâd like to get my hands on that wise guy, if only for Sandy MacPhersonâs sake,â Joe said. âHe works hard to keep his boats in good condition.â

Frank brought the car to a stop in front of a telephone booth. âIâm going to phone Sandy now. Just by chance, he might be able to give us a description of the car.â

Frank dialed the boatmanâs number, but there was no answer. âThatâs funny,â the boy remarked. âMacPherson doesnât answerâand he lives in the rear of his office.â

âMaybe heâs out on the dock and canât hear the phone ringing.â

âPerhaps,â Frank said. âLetâs drive back there.â

In a few minutes the boys arrived at MacPhersonâs dock. They noticed a dim, irregular pattern of light streaming through his office window, as if from a lamp that had been overturned. The boys hastened to the small building and peered inside.

MacPherson was lying face down on the floor.

âI think heâs unconscious!â Frank exclaimed.

The Hardys rushed inside to help him. As they turned him face up, the boatman groaned. âThat brigandl He was here again!â

âWhat happened?â Frank asked quickly.

âCardillo came back! He wanted me speedboat. I told him no. That devil said he would take the Ira Q, anyway.â

âEasy now,â Frank told the distraught man. âThen what happened?â

âI told him heâd have to step over me to get to it. He mustâve had friends with him, because I was suddenly hit from behind!â

Sandy MacPherson rose shakily and rubbed his head.

âCall the harbor police, Mr. MacPherson!â Frank said quickly. âJoe and Iâll take the Sleuth and search for your boat. Thereâs a chance it still may be out on the bay.â

âWatch out for foglâ MacPherson said. âItâs forecast.â

âWe will,â Frank assured him.

The boys drove to their boathouse, untied the Sleuth, and sped out onto Barmet Bay. Joe manned a portable searchlight, and swept the beam back and forth across the water.

âMacPherson was right about the weather forecast,â Frank observed. âFog is beginning to move in.â Joe used the portable light intermittently so as not to be dazzled by its glare.

Nearly an hour passed. By now the Hardys were far out in the bay. They were about to turn back when Joe directed the beam of his searchlight slightly off the port bow.

âIâve spotted something!â he exclaimed. âIt looks like a boat!â

Frank swung the Sleuth toward the object. It presented a ghostlike image through the haze.

âItâs the Ira Q!â Joe yelled triumphantly.

âNobodyâs aboard!â Frank responded.

The boys guided the Sleuth alongside the craft. Joe was about to board it when three men suddenly sprang from behind the gunwale. One struck Joe on the head with a blow that sent him crashing back into the Sleuth. A split second later two of the men clobbered Frank. He slumped unconscious.

CHAPTER II

The Missing Witness

âWHATâwhat happened?â Joe moaned as he regained consciousness.

Frank, still groggy, had already managed to get himself to his feet. âWe were jumped by three men hiding aboard the Ira Q.â

âCardillo mustâve been one of them,â Joe surmised.

The boys reached into the salty water and bathed their bruises. Then they scanned the dark sea.

The mist had thickened and there was no sign of the Ira Q. Before they could start their stalled motor, the Hardys heard the piercing sound of a foghorn. It was followed by shouts.

âAhoy! Ahoy! Is anybody out there?â

âMust be the harbor police!â Joe said.

The boys yelled in reply. Soon the running lights of the police boat loomed out of the fog. A small radar antenna revolved atop a mast on the cabin roof.

âYou must be the Hardys!â an officer cried. âMacPherson said you were out here! We found his boat!â

The boys glanced over the stern of the police craft. In tow was the Ira Q.

âDid you find anyone aboard?â Frank asked.

âNo. The boat was abandoned. We almost ran it down!â

Frank and Joe were mystified. Where could the three men have gone?

After telling the harbor police officers what had happened, the Hardys followed them back to MacPhersonâs dock. Sandy, along with Police Chief Collig, greeted them.

âWhatâs all this about?â Chief Collig asked, and was promptly brought up to date on the Cardillo case.

âThereâs not much to go on,â the chief commented. âBut Iâll alert my men. Chances are those scoundrels will show up again.â

The boys thanked the harbor police, berthed the Sleuth for the night, and drove home.

They were met at the door by their mother, a slim, attractive woman. âWeâve been worried about youâout in this fog,â she said. âOh, look at those awful bruises! What happened?â

âNothing serious, Mother,â Frank told her. âJoe and I just tangled with some crooks and came off second best.â

âCrooks? Criminals, you mean!â The voice was that of Aunt Gertrude Hardy, a tall, angular woman who breezed into the room. âGood gracious! I hope youâre not involved in another mystery!â

âHello, Aunt Gertrude,â Frank said with a grin. âDonât worry about us. We can take care of ourselves.â

âIndeed!â Aunt Gertrude sniffed. âWhat about those bruises on your heads?â

âWe just forgot to duck,â Joe quipped.

âOh! Teen-agers!â Aunt Gertrude scolded. âYour mother and I have been keeping a fine dinner warm. Come on. Sit down.â

Gertrude Hardy, unmarried sister of Mr. Hardy, had come to live at her brotherâs home. She was fond of her nephews, but thought that detective work was too dangerous for them.

The boysâ mother smiled affectionately. âYes. Come eat. Aunt Gertrude made you an apple pie for dessert.â

Frank and Joe had just finished their second helping of pie when Fenton Hardy arrived home.

âHi, Dad!â Frank said cheerfully.

âHello, boys. You look well-fed.â

âHow was your visit to New York?â Joe asked as they went into the living room.

âFine,â replied the tall, middle-aged detective. âIâd have been home earlier, but I had to take the train. The airport was fogged in.â

Mr. Hardy, youthful looking for his years, greeted his wife, then sat in a large wing chair.

âWait till you hear what happened to us today,â Joe said. He recounted the stories about the periscope and the Ira Q.

âVery mysterious,â Mr. Hardy remarked. âAnd you say you saw the periscope in the bay? Maybe it had something to do with Cardillo.â

Joe frowned in disbelief. âDo you think thatâs possible?â

âWeâd have an awful time proving it,â Frank said, âunless the Coast Guard comes up with something.â

âWhat about the Sleuth?â their father asked. âWas it badly damaged?â

âA dent, thatâs all,â Joe replied. âBut not serious enough to keep us from our fishing trip.â

The detective leaned forward, slapped both his knees, and looked disappointed. âIâm afraid I wonât be able to go.â He sighed. âI must start working on the New York case right away.â

âOh nuts!â Joe exclaimed.

âCan you tell us about your case?â Frank asked.

Mr. Hardyâs brow creased. âIt seems that a group of scoundrels has been peddling worthless stock in New York and New England. It has been sold in the name of a Mexican firm called Costa QuÃmico CompaÃ±ia. Thatâs Spanish for Coast Chemical Company.â

âI read something about that fraud,â Frank interrupted. âDidnât several Bayport people buy some of the stock?â

âYes. Like others, they were extremely gullible people who can be talked into a fast deal.â

Mr. Hardy told the boys that the authorities were not certain as yet how the fraud was being worked. However, the Securities Exchange Commission had filed indictments against three men in New York.

âBut to get a conviction,â the detective explained, âthe authorities are depending on the testimony of Elmer Tremmer, a Bayport bookkeeper, who kept records for the swindlers. Tremmerâs not too bright, but heâs honest. Itâs believed he was innocently involved in the fraud.â

âWhatâs the problem?â Joe questioned. âWonât he cooperate?â

âOn the contrary,â Mr. Hardy said. âIâm told he was eager to testify. Four days ago he went to New York and checked in at a hotel. He was scheduled to appear at a preliminary hearing the following day. However, Tremmer disappeared shortly after his arrival and hasnât been seen since. My job is to try and find him.â

âDo you think he was kidnapped?â Frank asked.

âPerhaps,â his father replied. âOr scared off.â

After Mr. Hardy finished outlining his new case, it was late and the boys went to bed. Early the next morning they received a telephone call from their buddy Chet Morton.

âHi, Chet!â Joe said. âThis is a great honorâyour getting up so early to phone us.â

âStow the funny talk. I called to ask if you and Frank are going out in the Sleuth today?â

âWe didnât plan to, but we can. Why?â

âIâll tell you later. Itâs a surprise!â Chet announced excitedly. âMeet me at your boathouse in an hour, and youâll witness the marvel of the century!â

As the Hardys drove off to the rendezvous, Joe said, âWhat do you think Chet is up to?â

âHe probably has some new hobby,â Frank replied. âWhatever it is, we can be sure of one thing. Itâll be good for a laugh.â

Chet, plump and jovial, lived on a farm outside Bayport. He was always experimenting with one hobby or another. Many were short-lived, but once in a while they were useful for the Hardys in solving a mystery.

The young detectives arrived at their boathouse just as Chet came rumbling along in his fatherâs farm truck. On the rear of it was an odd-shaped contraption hidden under a tarpaulin. Chet pulled up and hopped out.

âNow for the unveilinglâ he announced. âIf you fellows were wearing hats, Iâd tell you to hold onto them real tight. Youâre in for a whale of a treat!â

He flung aside the tarpaulin with one swoop. Resting on top of two metal pontoons was a bare wooden frame, triangular in shape. At the apex was a delta-wing of thin, light fabric.

âWell, what do you think of it?â Chet asked proudly.

Joe stared at the contraption. âItâs neat. But what is it?â

âYouâre looking at the Marvelous Morton Water Kite!â Chet said.

âSounds impressive,â Frank commented. âWhat does it do?â

âThat should be obvious! My masterpiece will float on the waterâsee the two pontoons? You guys are supposed to tow me around the bay. Then, when we get up enough speed, the delta-wing will carry me into the air like a sea gull.â

âPretty dangerous!â Joe muttered.

âNothing doing!â said Frank. âThat gadget looks too tricky to be handled by an amateur.â

âAw, come on,â Chet pleaded. âIâve spent a lot of time building this.â

Chet was so persistent that the Hardys finally consented to tow him. But they urged their friend not to try anything fancy until he acquired some experience in controlling the kite.

While the Hardys untied the Sleuth, Chet changed into his swim trunks and extended a long line of nylon rope from the kite to the Sleuthâs stern. Then he strapped himself to a small seat aboard the winged contraption.

âAll set?â Joe yelled to his friend.

âHaul away!â Chet responded.

Frank advanced the throttle and the Sleuth moved ahead.

âFaster! Faster!â Chet shouted.

Frank increased speed, then he glanced back to see how the experiment was progressing. The fabric wing became rigid and the kite bounced a couple of times, then lifted a few feet off the water.

âLeaping lizards! Look at that!â Joe exclaimed.

âMore speed!â Chet ordered.

Frank increased the power. Suddenly the kite went into an abrupt climb high above the water.

âChet! Be careful!â Joe shouted.

At that instant the towline went limp and fluttered down toward the water.

âHelp!â Chet shouted as the towline snapped.

âHeâs in free flight!â Frank yelled. âAnd gliding toward the shore!â

As the kite passed over land, a warm, vertical air current carried it up even higher. The boys watched helplessly as Chet vanished over the crest of a hill.

âHelp!â Chet shouted as the towline snapped

Speeding back to the boathouse, they leaped into their car and drove off in pursuit. Five minutes later Joe pointed to a knot of people peering at a factory chimney. Cries for help were coming from the stack. Chet was hanging on courageously.

Sirens wailed as the Bayport Fire Department and Police Emergency Squad vehicles screamed to the scene. Reporters and photographers rushed to record the rescue as Chet and his kite were untangled and brought to safety on a towering aerial ladder.

Chief Collig arrived to make sure the situation was under control. When he spotted the Hardys, he hurried over to talk to them.

âI tried to contact you boys a couple of hours ago,â the chief said. âOne of my men came across an unlocked car in a parking area near MacPhersonâs dock. No one knew who owned it, so we decided to run a routine check. The car was sold by a dealer in New York to a man named Pancho Cardillo! The address on the registration is fictitious.â

âIâll bet Cardillo is not his real name either,â Joe commented.

âIf you boys would like to take a look at the car,â Collig said, âyouâll find it at the police garage.â

âWeâll do that,â Frank answered.

The Hardys drove a subdued and badly frightened Chet back to his truck, then hastened to the police garage. There they examined the car minutely. Frank noticed a small object jammed underneath the gas pedal. Pulling it out, he saw that it was a broken finger ring with a strange insignia on it.

âLook, Joe. Indian craftsmanship, Iâll bet.â

âAztec, Iâd say,â Frank said.

The insignia was a cluster of faggots from which a flame issued, with a large letter P in the center of the design.

âMaybe itâs a family crest,â Joe suggested.

Frank dropped the ring in his pocket. Then he and his brother drove home. As they entered the house, intending to show the ring to their father, he summoned them to his study. Mr. Hardy was holding a white sheet of letter-size paper.

âThis just came a few minutes ago,â he said. âFrankly, Iâm baffled. I donât know what to make of it.â

He handed the letter to his sons. Their eyes widened when they saw the typewritten message:

BEWARE OF THE MARK ON THE DOOR!

CHAPTER III

The Strange Symbol

âWHAT mark on the door?â Frank asked. Joe hastened out to examine their front and back doors and the garage as well.

âNo signs there,â Joe said when he returned.

âThe envelope was postmarked Bayport,â Mr. Hardy said, âwhich brings the mystery right to our doorstep.â

âIt could be a prank,â Frank said.

âYou might be right,â their father replied. âBut I suggest we all be very careful.â

As the boys took comfortable chairs in their fatherâs study, Mr. Hardy filed the mysterious warning and turned his attention to a thick dossier on his desk.

âIâve been going over the information given me concerning the stock-fraud case,â he said. âVery interesting. Iâm sure you boys would like me to fill you in.â

âWe sure wouldlâ Frank answered quickly as he and Joe pulled their chairs closer.

âIâve already told you,â the detective went on, âthat the worthless stock was sold in the name of the Costa QuÃmico CompaÃ±ia.â

The boys nodded.

âAccording to this information, the plan to start the chemical firm was the idea of SeÃ±or JosÃ© Marcheta, a retired chemical engineer and a highly respected resident of Vivira, Mexico.â

âWhat made a man with his reputation go wrong?â Joe queried.

âThatâs just it!â the detective answered. âThe facts indicate that Marcheta is not really part of the fraud.â

He explained that the engineer was sincere in his efforts to create a firm for the refining of chemicals. His principal aim was not only to develop one of Mexicoâs great natural resources, but to bring work to the people of the area. It appeared, however, that Marcheta had become the target of extremely clever swindlers, who used his efforts as a front for a stock fraud.

âWhat does Senor Marcheta have to say about all this?â Frank asked.

âHe was questioned by the United States consul in Guadalajara, Mexico,â Mr. Hardy explained. âHe denied knowing anything about the scheme, or any of those involved.â

âBut he must know something about the men behind the plot,â Joe insisted.

âIâm sure he does,â Mr. Hardy agreed. âNevertheless, Marcheta isnât saying anything. And itâs obvious why. The consulâs report states that he appeared badly frightened. Whoeverâs behind the fraud must have come up with a strong enough threat to keep him from talking.â

Frank and Joe mulled over the situation until bedtime. The next morning, Sunday, was chilly and rainy. The boys planned to do nothing more that day than to attend church, catch up on their reading, and ponder the mysterious events of Friday and Saturday.

After a leisurely dinner, the Hardys began to skim through the voluminous Sunday newspaper. Joe burst out laughing when he saw that Chetâs water-kite escapade, complete with pictures, had made page two.

Frank was scanning another section when he suddenly sat bolt upright. âWow!â he exclaimed, and quickly tore out a small news item. âTake a look at this!â

Joeâs eyes widened in amazement at what he saw. The news story, datelined Mazatlan, Mexico, read:

A local fisherman has reported sighting an unknown submarine off the Sinaloa coast, approximately 140 miles northwest of Mazat-Ian. The sighting, according to police here, took place on Friday, but the report was not released at that time, pending an investigation by the Mexican Coast Guard.

Questioned by the authorities, the fisherman described an insignia painted on the conning tower of the craft. In his words, it âappeared to be flames issuing from a bundle of sticks, with the letter P in the center.â

A spokesman for the Coast Guard said that a search revealed no evidence of a submarine in the area.

âIt sounds impossible!â Joe said as Frank dashed to get the broken ring he had found in Cardilloâs car. The boys showed it to their father, along with the clipping.

The detective was amazed as he examined the ring. âWhy, the design is similar to the one the fisherman described!â

âExactlylâ Joe exclaimed. âThere must be some connection between Cardillo and the sub. Maybe he escaped in the one we saw in the bay.â

âNow hold on a moment,â Frank said. âIf Cardillo did escape from Barmet Bay by submarine, it couldnât possibly be the same craft the fisherman spotted. It would take weeks for it to sail there!â

âYouâre right,â Joe agreed. âBut there could be more than one. What if Cardillo is a member of a gang that uses submarines?â

âIntriguing theory,â Mr. Hardy mused.

As they continued to discuss the mystery, the telephone rang. Frank scooped up the receiver. âOh, hello, Chief Collig.... Whatâs that you say?â Frank listened for a few seconds, his expression taut with excitement. âOkay, Chief. Iâll tell him. Good-by.â

Frank whirled around. âDad! Joe! Listen to this! The chief said that one of his men from the crime lab examined Cardilloâs car for fingerprints. It was clean except for one clear specimen on the handle of the right rear door. The print belongs to Elmer Tremmer!â

âThatâs a tremendous clue!â Mr. Hardy cried. âThis means Cardillo might have had something to do with Tremmerâs disappearance!â

âWhich suggests,â Frank added, âthat Cardillo could be mixed up in the stock fraud!â

âBut what about the submarine angle?â Joe said. âThere are faster and easier ways of escaping.â

Mr. Hardy rested back in his chair to think. âIâm beginning to believe thereâs more to all this than a missing bookkeeper and the peddling of worthless stock,â he said finally. âAlso, the various bits of information weâve collected so far have one thing in commonâtheir connection with Mexico!â

Joe sighed. âThatâs a long way off.â

âTrue,â Mr. Hardy said. âBut it might prove worth while for us to go to Mazatlan.â

âUs?â Frank cried out. âYou mean Joe and me?â

âOf course. This is an important case. How about it, Joe?â

âRoger, Dadlâ

âSeÃ±or Marchetaâs home in Vivira is not far from Mazatlan,â Mr. Hardy went on. âIâd like to take a crack at talking to him myself. Perhaps I could get Marcheta to give me some useful information.â

âAnd Joe and I can check on the fishermanâs story,â Frank suggested. âIf we can track down the sub, you can be certain the trail will lead us to Cardillo ...â

âAnd Tremmer!â Joe interjected.

âExactly what I had in mind,â Mr. Hardy said. âYour lead is strong enough to make it worth the try. But since Iâm working with the investigators of the Securities Exchange Commission, Iâll have to get their okay.â

Next morning Mr. Hardy made a telephone call to a man in New York. He then joined his sons at breakfast to tell them that he had been given the green light to go to Mexico. Frank and Joe let out a loud cheer.

âFiddlesticks!â Aunt Gertrude snapped as she placed a heaping platter of hot wheatcakes on the table. âRushing off to the ends of the earth again! I just donât know what to make of this family.â

âTheyâre certainly on the go,â Mrs. Hardy said, serving the griddlecakes.

Joe laughed. âMexico isnât so far off.â

âBut enough to cause your mother and me a lot of worry,â Aunt Gertrude retorted. âI should think thereâd be plenty for detectives to do right around here.â

Mr. Hardy planned to use his own sleek, single-engine airplane for the trip. He instructed his sons, both fliers themselves, to contact Jack Wayne, their pilot, to make arrangements. âLetâs try to get off today,â he said.

Joe rushed to the telephone. Soon he had Wayne on the line.

âMazatlan, Mexico, you say? Hold on while I get my air charts.â There was a brief silence, then the pilotâs voice came on again. âAs I see it, weâll have to make two refueling stops. The first at Memphis, Tennessee, and the second at Brownsville, Texas.â

âHow long do you estimate the entire trip will take?â Joe asked.

âRoughly, about fourteen hours of flight time to Mazatlan,â Jack replied. âIf we leave within the next couple of hours, we can be in Brownsville by eleven or twelve oâclock tonight, Texas time. Then weâll hole up there till morning. Itâll not only give us a chance to get some sleep, but also we wonât have to tackle those Mexican mountain ranges in the dark.â

âGood! Weâll see you at Bayport field as soon as we pack.â

âOne more thing,â the pilot added in conclusion. âMexico requires that everybody have a tourist card to visit the country. Also, Iâll have to file a special flight plan to Mazatlan. But we can take care of all that in Brownsville.â

Frank rushed into the room just as Joe finished his telephone call. âGuess what?â he said. âDad suggested we ask Chet to go along.â

âGreat idea!â

Chet readily accepted and received permission from his father.

The Hardys began packing. Finally they were ready to leave for the airport. Mrs. Hardy kissed her husband and sons as they said good-by. She was aware of the dangers involved in their work, but seldom allowed her concern to be known to them.

Aunt Gertrude shook her head dolefully. âNo good will come of this! Mark my words!â she prophesied. âBut please be careful,â she added, pecking the embarrassed boys on their cheeks.

Chet was ready when the Hardys drove up, and soon the group arrived at Bayport field. They found Jack Wayne seated in the plane. Within minutes the craft took off. The weather was exceptionally clear, and the terrain below presented a vivid picture in the sparkling sunlight.

The refueling was made without incident, and it was nearly midnight when the Hardy plane touched down on the runway at Brownsville. Jack and the others wasted no time checking in at a nearby hotel.

After breakfast the next morning they went directly to the Mexican Tourist Bureau to obtain their tourist cards. Jack Wayne filed the necessary flight plan to Mazatlan and soon the travelers were winging off on the final leg of their flight.

Frank and Joe were particularly awed by the country over which they were flying. Beneath them was a mixture of open plains and bleached deserts. Mountains jutted up on all sides, and some of these seemed to Chet to be higher than their own altitude.

As they neared their destination the group gazed down on a solid layer of stratus clouds.

âLooks like bad weather rolling in from the coast,â Frank observed.

Jack agreed. âIâve been watching it. Iâd better contact Mazatlan and see whatâs up.â

The pilot switched on the radio. It crackled for an instant, then was silent. He turned on the stand-by radio. Nothing! Jack tapped the radio compass and other navigational equipment vigorously. âOh, nolâ he muttered.

âTrouble?â Mr. Hardy queried.

âAll our radios have gone out!â the pilot replied anxiously. âWe must have a short in the electrical system.â

âAnd we donât know what the visibility is like below that cloud layer!â Frank declared. âIf itâs zero-zero, weâd have to make an instrument approach. Thatâs something we canât do without our radios!â

âAt least weâre west of the Sierra Madre Mountains,â Joe commented. âWe donât have to worry about running into those.â

âWhat about turning around and going back?â Mr. Hardy suggested. âThe weather is clear east of the mountains.â

Jack turned and scanned the area behind him. âIâm afraid thatâs out! Take a look yourselves!â

The Hardys and Chet turned to see a frightening sight. Towering cumulo-nimbus cloudsâthunderstormsâwere already developing along the windward side of the mountains.

âWe could never climb high enough to get over those storms!â the pilot said. âAnd to fly through them would be suidde!â

âThen weâre trapped!â Joe exclaimed.

CHAPTER IV

The Hostage

FRANK frantically tried to get the radios working, while Jack Wayne flew in a continuous circle to maintain their position over Mazatlan.

âNo good!â Frank finally declared, âWeâll have to do the best we can without the radios!â

Chet groaned and Mr. Hardy looked grim. Jack suddenly straightened the plane out on a westerly course. âIâm going to try something,â he said.

âWhat?â Joe questioned nervously.

âThe cloud layer doesnât extend too far out to sea,â Jack answered. âIâm going to let down over the water in the clear. From there, we can see whether thereâs enough of a ceiling for us to get into Mazatlan.â

The boys stared ahead as the pilot began his descent. After they had passed beyond the edge of the cloud layer, he dived the plane as low as he dared, then turned east toward the coast.

âWeâre in luck!â Frank exclaimed. âThereâs a ceiling of at least two or three hundred feet!â

âYes,â Jack agreed. âBut the visibility isnât too good. However, if weâre careful, we should be able to make it. Letâs hope it doesnât get any worse.â

The plane was now flying just above the surface of the water. Frank and the others peered ahead into the mist.

Suddenly Joe pointed off to his left. âI see something out there! Or is it just a band of dark clouds?â

The pilot leaned forward in his seat. âThatâs the coast of Mexico!â he cried jubilantly.

As they flew closer, various features of the terrain became more clearly defined. Frank unfolded a chart and compared the coastline they were approaching with the map profile.

âThat wide inlet directly ahead, with a peninsula of land jutting out from the left, matches the shape of the coastline on the map where Mazatlan is located!â he exclaimed.

Gradually a sprawling city began to appear out of the mist.

âIt is!â Mr. Hardy shouted. âCongratulations, Jack! Youâve hit it right on the nose!â

âLucky again,â the pilot said jokingly. He rolled the plane into a left turn. âThe airport should be a couple of miles north of the city.â

In less than a minute they spotted a bright, white rotating beam from a beacon atop a building. Immediately adjacent to it, the outlines of runways began to take shape.

âThereâs the field!â Jack declared.

âI was never happier to see anything in my whole life.â Chet sighed with relief.

âSince our radios are out, I canât communicate with the control tower,â Jack explained. âIâll circle the field and wait for a green light.â

The pilot had just completed two circuits of the airport when a disk of green light glared from the tower. The pilot responded by banking the wings of the aircraft to the left and right several times. He then checked the wind tee to determine which runway was being used for landings. Shortly thereafter the Hardy plane touched down at Mazatlan.

In the terminal building the group underwent a routine check by customs officials, then Mr. Hardy called for a taxi.

âThere wasnât time to make hotel reservations in advance,â he announced. âBut we shouldnât have too much trouble this time of year.â

Soon the group was in a cab heading for the city proper. Despite the gray skies, the vivid green of the lush tropical scenery raised their spirits. As they sped along the Avenue del Mar, they could see the choppy waters of the Pacific and the mouth of the Gulf of California. People strolled slowly along the streets, men wearing colorful sarapes and women with rebozos draped over their heads and shoulders.

Arriving at a hotel, Mr. Hardy dashed inside. He reappeared after a long wait. âThe hotels are busier than I thought,â he told Jack Wayne and the boys. âWeâll have to take a suite. The clerk phoned several other places for me, but they donât have anything else either.â

When they were ushered into the rooms, Chet plunked himself into a comfortable chair. âNow this is what I call real luxury,â he said âWhen do we eat?â

âJust as soon as we freshen up,â Frank answered.

âGood! Iâm not used to going without food this long,â Chet complained. âWe missed lunch, and my watch tells me itâs almost time for supper.â

Joe glanced at his chumâs corpulent waistline. âYouâre stocked with enough reserve to last for weeks!â

Frank turned to his father. âWhatâs first on your agenda, Dad?â

âA talk with Senor Marcheta,â Mr. Hardy replied. âIn the morning Iâll rent a car and drive to Vivira to see him.â

âMeanwhile,â Frank said, âJoe, Chet, and I will try to locate the fisherman who reported sighting the sub. Perhaps the police will tell us where we can find him.â

âI have my work cut out for me too,â announced Jack Wayne. âIâll head for the airport first thing tomorrow to see about getting the radios repaired.â

When they left the hotel to find a restaurant, the weather had improved and a magnificent sunset was visible. Palm trees swayed in a gentle breeze and the chatter of myna birds and parrots could be heard.

As the group strolled along, Chet gazed at the first seafood restaurant they came to with such a hungry expression that the others permitted him to lead them into it. After a hearty meal they walked back to the hotel. Chet, burdened down by the two large lobsters he had devoured, trailed behind the others at a snailâs pace.

As they entered the lobby, the desk clerk handed Mr. Hardy a message. The detective ripped open the sealed envelope, read the letter inside with a startled expression, and quickly handed it to Frank and Joe. They were equally surprised. The hand-printed message read:

GET OUT OF MAZATLAN, ALL OF YOU! YOUâRE IN GREAT DANGER!

Mr. Hardy turned to the desk clerk. âWho gave you this message?â

âA boy came in with it about twenty minutes ago, sir,â the clerk answered. âHe said some man paid him two pesos to deliver it.â

The Hardys and their companions hurried to their suite.

âWho could possibly know weâre here?â Frank muttered as he examined the message again.

âPerhaps someone at the airport saw the flight plan I filed to Mazatlan,â Jack Wayne suggested. âI not only have to list the number of passengers aboard, but also your fatherâs name and address as owner of the plane.â

âEven so,â Mr. Hardy commented with a puzzled expression, âno one here knows who I am.â

âTremmer does,â Joe stated. âAnd that means Cardillo would also.â

âI thought you fellows said that those guys left Bayport by submarine,â Chet interrupted. âTheyâd have to travel like a rocket to beat us to Mazatlan.â

âYouâre right,â Frank said with a sigh. âBut hey! What if Cardillo didnât stay with the sub? He might have traveled just a short way, then gone ashore near an airport where he could catch an airliner to Miami. From there, he could fly direct to Mexico City, then by private plane, or feeder line, to Mazatlan.â

âBut if Cardillo intended to fly,â Joe queried, âwhy bother with the sub at all?â

âThatâs a question I canât answer right now,â Frank admitted.

âMaybe he suddenly discovered that he had claustrophobia,â Chet quipped, âand couldnât stand to be boxed in.â

âIn any event,â Mr. Hardy announced, âwe have to assume that Cardillo and Tremmer know weâre here. And that calls for an immediate change in my plan! Iâm going to try and see Senor Marcheta tonight. I hope it isnât too late already!â

âWeâll go with you,â Frank declared. âThere may be trouble.â

Jack Wayne was instructed to tend to the planeâs radio repairs, while the boys leaped into a rented car with Mr. Hardy.

âVivira is less than forty miles north of Mazatlan,â Frank said, examining a road map. âJust off the main road.â

A little over an hour passed before the Hardys and Chet arrived in Vivira. It was a quiet little village with many trees, and a fountain in the center of a small plaza. Standing near the fountain was a young man.

âDonde esta el hacienda de SeÃ±or Marcheta?â Frank asked the Mexican in his best high school Spanish.

The man did not answer. He eyed the Hardys and Chet for a moment, then pointed toward a large hacienda surrounded by a high stone wall, at the far end of the street.

âGracias!â Frank said.

âAdios!â Chet called from the rear window.

At the spot the man had indicated, Mr. Hardy and the boys got out of the car and walked toward a decorative wrought-iron gate. Set in the wall beside the gate was a metal handle. Joe gave it a hard yank and a bell tinkled. Shortly a slim, tall man appeared, silhouetted in the doorway of the hacienda.

âQuiÃ©n es ello?âWho is it?â he asked.

âAre you Senor Marcheta?â Mr. Hardy asked.

âSi!â

âWeâre visitors from the United States. My name is Fenton Hardy. Iâd like to talk to you.â

âNorte Americanos? You wish to talk to me? Why?â

âPlease, Senor Marcheta,â the elder detective pleaded. âI wonât take much of your time. Itâs important!â

The senor slowly walked toward his visitors. As he approached in the dim light the boys saw that he was an elderly, gray-haired man with a mustache and goatee. He had a kindly face and a manner that immediately commanded respect.

Mr. Hardy introduced his sons and Chet. Marcheta studied them for a moment. âI cannot deny you the hospitality of my home,â he said finally. âCome in.â

He led the visitors into his hacienda and motioned to them to be seated. âNow what is it you wish to speak to me about?â he queried.

âIâll get right to the point,â Mr. Hardy said. âIâm working on a case connected with a stock fraud involving the Costa Quimico CompaÃ±ia.â

Marcheta turned pale. âI have already been questioned by members of your consulate in Guadalajara!â he cried. âI tell you, as I told them, I have no information to givelâ

âSeÃ±or Marcheta, please be patient,â Mr. Hardy replied. âWeâre only trying to help you. If you can tell me anything at allââ

âNo! I cannot!â the elderly man retorted. âYou must understand. It is not for myself that I am afraid. I fear for the life of my son Juan. They have taken him away! I ...â His words trailed off. He buried his face in his hands and sank into a chair.

âSo thatâs it,â Mr. Hardy muttered. âThose scoundrels are holding your son as a hostage!â

âThat should be reason enough for you to give us your cooperation,â Joe put in.

âNo, no!â Marcheta exclaimed. âI did not know what I was saying! You must go now!â

âWe realize the situation youâre in,â Frank said solemnly. âBut if you think youâre going to help your son by keeping this to yourself, youâreââ

At that instant a large stone came crashing through the window and landed in the middle of the room.

âWhatâs that?â Chet cried.

âEverybody get down!â Frank shouted.

Mr. Hardy pulled Marcheta out of his chair to the floor. Then Frank, followed by Joe and Chet, ran out of the house.

âSpread out and search the area!â Frank ordered. âYell if you see anything!â

The boys groped their way through the darkness. As Frank neared the rear of the hacienda, a man suddenly sprang from behind a bush several yards away and pulled what looked like a coiled bullwhip from his belt. Then a long raw-hide tentacle lashed out toward Frank!

CHAPTER V

Danger Path

SWISH! The end of the whip stung Frankâs ankles and wound tightly around them! The man gave a sharp tug, and the boy crashed to the ground.

Quick as a cat, the man retrieved the whip and lashed out at a branch of a nearby tree. The slender tentacle coiled around the branch to form a clove hitch. As Frank scrambled to his feet, the intruder used it to swing himself, trapeze-fashion, to the top of the wall. The next instant he was gone!

The other boys came running. âWhat happened? Are you all right?â Joe shouted.

âI ran into the man weâre looking for,â Frank explained, rubbing his ankles. âAnd heâs mighty handy with a whip.â

The three boys returned to the hacienda to find Marcheta in a state of panic. âAll is lost!â he cried. âI shall never see my son again!â

When Mr. Hardy heard Frankâs story, he handed the boys a piece of paper. âThis was wrapped around the rock,â he said.

On it was a drawing of flames issuing from a cluster of branches with the letter P in the center. The symbol again! Under the drawing was a message written in Spanish. Translated, it read:

We are aware you have visitors! This could mean Juanâs doom!

âSeÃ±or Marcheta,â Frank said quickly, âdo you know what this symbol stands for?â

âI do not! Nor do I care! The safety of my son is all that concerns me!â

âIf you really mean that,â Mr. Hardy said, âyouâll let us help you.â

âIt is because you are here that my son is in greater danger than ever!â Marcheta insisted.

Mr. Hardy stroked his chin thoughtfully, and turned to the seÃ±or. âThereâs one way we might be able to protect your sonâfight fire with fire. SeÃ±or Marcheta, you must go into hiding!â

âYou mean leave here? Never! Never! Not while Juan is in their hands!â

âBut itâs for your sonâs sake,â Mr. Hardy urged. âIf you were to disappear, the kidnappers would begin wondering what youâre up to. Until they knew, Iâm certain they wouldnât harm your son. Heâs their only insurance that you wonât go to the authorities.â

The senor nervously shifted in his chair. After thinking the plan over, he said slowly, âPerhaps you are right. But I will not leave Mexico.â

âHow about Mexico City?â Joe suggested. âItâs easier to hide out in a populated place.â

âGood idea,â Mr. Hardy agreed.

âWhat about SeÃ±ora Marcheta?â Frank inquired.

âI sent my wife away for her own protection. Only I know where she is. As for your plan, it is a fine one. How do you propose to do it?â

âWeâll have to figure out how to get you away without being seen,â Mr. Hardy explained. âThen you can be flown to Mexico City in my plane.â

âBut we canât risk going to Mazatlan Airport,â Frank warned. âWe already suspect that the gang has a spy there.â

âHow about having Jack fly here?â Joe said. âThere must be lots of level country nearby.â

âThere is a large cattle ranch approximately six miles north of Vivira,â Marcheta replied. âIt is very flat and would be ideal for your purpose.â

âThen itâs settled!â Mr. Hardy declared. âBut to insure absolute secrecy, weâll have Jack fly to the rendezvous point after dark. Itâs too late now, so it will have to be tomorrow night.â

The Hardys outlined their plan. The detective and the boys would remain with Marcheta that night to make sure no harm would come to him. In the morning one of the boys would drive to Mazatlan to give Jack Wayne his instructions, then return to the hacienda to take Mr. Hardy and Senor Marcheta to the cattle ranch.

âBut thereâs still the problem of getting Senor Marcheta out of the hacienda without being seen,â Joe commented.

âIâve been thinking about that,â Frank said. âAnd I have an idea.â

âHow about letting us in on it?â Chet urged.

âIâm almost the same height and build as Senor Marcheta,â Frank declared. âIf you will lend me some of your clothes, senor, Iâll improvise a disguise that might fool whoeverâs spying on us.â

âCould such a plan work?â the seÃ±or asked.

âItâs worth a try,â Frank replied. âJoe and Chet should go with me to make it appear that Iâm in need of protection. Weâll leave first thing in the morning.â

The Hardys and Chet took turns standing guard during the night. In the morning Frank donned a suit of clothes Marcheta gave him, then ground some white chalk into powder and sprinkled it into his hair.

âVery clever,â Marcheta commented with a grin. âYour hair is now almost as white as mine.â

Next, Frank pulled a bit of stuffing from a worn chair, whitened it with chalk, and fashioned a mustache and a goatee for himself. A straw hat completed the disguise.

âYouâve done a terrific job,â Mr. Hardy said.

âThanks, Dad. Keep your fingers crossed. I hope it works.â

âJust one question,â Joe interposed. âWhoeverâs watching the hacienda must know that there are five of us here. Wonât it look suspicious if we donât all leave together?â

âIâm hoping heâll think that two of us stayed behind to nab him if he shows himself,â Frank explained. He pulled the brim of the straw hat low over his eyes. âIâm all set to go! Hope this disguise works!â

The three boys hurried out of the house and made a beeline for their car. As they sped away, Joe, who was behind the wheel, glanced into the rear-view mirror and saw a man leap out from behind a tree.

âAt least one villager is interested in our departure,â Joe said. âI wonder if heâs our man.â

âWe canât take the time to find out,â Frank answered, and removed his disguise. Within the hour they arrived at the airport and quickly located Jack Wayne.

âHi, fellows!â the pilot exclaimed. âYouâll be glad to hear the planeâs radios are working again. There was a defective circuit breaker in the system.â

âGood,â Joe replied. âWeâre going to need you and the plane.â

The Hardys described their plan for the eve ning to Jack. When they had finished, the pilot told them how to set up the rendezvous point.

âHope this disguise works!â Frank said

âFind a long, level stretch of ground. Make sure there are no obstructions near the spot. Then aim the headlights of your car in the direction you want me to land. Once Iâm lined up, the planeâs landing lights will show me the way.â

âTry to make your departure as inconspicuous as possible,â Frank said.

âIâll file a flight plan back to Brownsville, Texas,â Jack replied. âThat should confuse anyone whoâs curious. I can always cancel it later.â

The boys drove into the city for a leisurely lunch. Then they went to their hotel to wait until dark. It was well into evening when Frank, Joe, and Chet joined Mr. Hardy and SeÃ±or Marcheta at the hacienda.

âYour disguise worked like a charm,â the detective told Frank. âShortly after you left, a man with a coiled bullwhip in his belt rode off on a horse. He certainly was in a hurry, judging by the amount of dust he was kicking up.â

âWeâd better get out of here,â Joe warned. âHe might decide to come back.â

The Hardys and their companions got into the car and took the road leading north from Vivira. Soon Senor Marcheta pointed to flat areas of land flanking both sides of the narrow road.

Frank pulled the car to a stop and got out, followed by Joe and Chet. Together, they searched for a suitable landing spot, and found one that was flat and as smooth as a table. Frank returned to the car and maneuvered it to point in the direction Jack Wayne was to land.

Several hours passed before the droning sound of a planeâs engine was heard. Frank switched on the headlights, then flicked them on and off several times. Minutes later the planeâs landing lights illuminated the area ahead, and the craft touched down in a gentle landing.

Jack Wayne taxied the plane in and Mr. Hardy and Senor Marcheta climbed aboard. Soon they were airborne. Chet and the young detectives watched as the plane disappeared in the night sky.

The Hardys and Chet drove back to their hotel in Mazatlan and turned in for several hours of sleep. After breakfast they went to the police station and asked for the name of the fisherman who had sighted the submarine.

The officer in charge told them that the report had not been kept on file and he himself had never seen it. He suggested, however, that they inquire along the docks.

The boys hastened to the area and made some inquiries. They had little success, until a Mexican youth, about Joeâs age, approached them.

âSeÃ±ores,â he said, âexcuse me, please, but I understand that you are looking for the fisherman who saw a submarine.â

âThatâs right,â Joe answered.

âMy name is Tico,â the Mexican boy extended his hand in greeting. âThe man you seek is Senor Ricardo. He is now fishing and will not be back for two or three days.â

The Bayporters introduced themselves and Frank asked if Tico knew anything about the fishermanâs report.

âOnly that he says he saw a submarine. I believe him, for I am sure that I have seen it too.â

âYouâve seen a sub?â Chet blurted. âWhen? Where?â

âMy father, who is also a fisherman, and I took our boat up the coast as far as Ensenada del Pabe lion about two weeks ago,â Tico explained. âOn the way back I was certain that I saw what looked like a submarine in a cove.â

âWhy didnât you report it?â Frank asked.

âI had too small a glimpse of it to be sure what I saw,â the youth replied. âIt was nearly sunset, and my father insisted the shadows were playing tricks with my eyes. I forgot about it until SeÃ±or Ricardo said he saw a submarine a few days ago.â

âYou speak very good English,â Chet commented.

âThank you,â Tico said with a smile. âMy father sends me to a fine school in Mexico City. He does not wish me to become a fisherman, but perhaps a lawyer. I study English.â

Frank thought for a moment. âDo you think you could find that cove again?â

âYesâyes, I think I could do this,â Tico assured him. âThe cove is best reached by boat. Unfortunately my father is away fishing, and Iâm on my own for about a month. We have a small craft with an outboard that will serve our purpose. The journey will take about four or five hours.â

âGood. Wait here for us,â Frank said.

The Hardys and Chet first went to the Mazat-Ian shopping district to buy clothes suitable for their intended expedition. By the time the boys returned to the dock, Tico was in his boat, ready to depart. They hopped in, and the Mexican boy set off.

Frank and Joe marveled at the scenery along the coast. It was extremely craggy, and geysers of white foam shot up from the sea splashing against the jagged rocks.

Soon the wind became more brisk. The surface of the water grew choppy, and Tico had to increase the power to keep from drifting toward shore.

âItâs blowing up a storm!â Joe warned. âWeâd better beach this boat!â

âToo rocky!â Frank disagreed. âThe boat would be smashed to pieces.â

As the small craft was being tossed violently about, the motor mount suddenly pulled free from its fittings. The entire unit disappeared into the water!

âCaramba!â Tico cried.

Frank and Joe found two paddles stowed underneath the seats. They grabbed them and made a valiant effort to keep the boat away from the craggy shore. But their attempt was futile. Despite their frantic paddling, the boat continued to be swept toward the jagged rocks!

CHAPTER VI

Mysterious Vigil

JoEâs paddle suddenly was ripped from his hands by the raging sea. The small boat was carried to the crest of a wave, and went skimming down the lee side toward the jagged rocks.

âHang on!â Frank shouted as water spilled over the gunwales.

Suddenly the craft capsized and the four boys were tossed into the sea.

âSwim for it!â Frank cried. âHead forâ!â He swallowed a mouthful of brine and coughed violently as he struggled through the maelstrom.

For a while the boys bobbed like corks in the turbulent sea, progressing for a few strokes, then being tossed back again. With arms flailing, they finally made it. Frank and Joe were the first to be hurled onto solid ground. Chet came next, fol lowed by the Mexican youth.

Tico lay panting for a few minutes. âI am happy to see that everyone is all right,â he finally said.

âSorry about your boat,â Joe remarked.

âIt could not be helped,â Tico said philosophically. âDo not worry.â

The boys walked a short distance inland. There the wind was less brisk, and a warm sun began to send shimmering waves of heat up from the bleached sand and rocks.

âItâs very desolate around here,â Frank observed. âWhere are we?â

Tico took a moment to orient himself. âWe are not far from the cove I spoke about,â he said. âIt is less than an hour from here on foot.â

âNo sense in turning back as long as we got this far,â Joe commented.

The boys agreed to continue on. With the Mexican youth in the lead they trekked ahead, and arrived at their destination in the time Tico had predicted.

âThere it is!â he exclaimed. âI know by that tall point of rock. It looks over the cove.â

They slowly worked their way down a steep incline of rock to the shore. At once the young sleuths began searching the area for clues.

âIf a sub was here,â Chet said, âyouâd never know it. Thereâs not a trace of anything but fish!â

He held his nose and pointed to a half-eaten sea trout that had been washed ashore.

Frank, passing a large rock nearly buried in the sand, noticed deep scratches on its surface. âTake a look at this, fellows,â he called out.

âHm! Looks like some kind of heavy objects were dragged over the ground,â Joe stated as he studied the marks.

âNotice that they continue,â Frank replied, âin a straight line toward that big boulder at the base of the incline.â

As the boys began walking toward the spot, a shot suddenly rang out! Then another! Splinters of rock sprayed in all directions.

âJumping jackals!â Chet yelled. âHit the dirt!â

Frank and Joe whirled to look up at the high rim of rock surrounding the cove. Two men, one taller than the other, mounted on horses, were silhouetted against the sky. Each carried a rifle, aimed in the boysâ direction.

Bam! Bam!

Two more bullets struck nearby as the boys scrambled along the craggy shore of the cove.

âQuick!â Frank ordered. âIn here!â

Followed by his companions, he darted into a narrow crevice. It led up the side of a steep hill, and eventually opened into a place which served as an excellent vantage point. From there, the boys could look up and see their attackers clearly.

âWhy did those men shoot at us?â Joe hissed angrily. âAre they bandits?â

Chet crouched low behind a rock. âIâm not curious enough to go out and ask them,â he declared.

âEverybody be quiet!â Frank commanded.

They watched as the two men, dressed in ragged clothes and sombreros, got off their horses and scurried down the rocky incline to the cove.

âTheyâre coming after us!â Tico whispered nervously.

âThere are many crevices along the shore,â Frank muttered. âLetâs hope they donât find the right one.â

Minutes ticked by slowly as the men searched. Once they came uncomfortably close to the boysâ hiding place. The taller man, his voice barely audible in the distance, said something to the other in Spanish. Then, apparently giving up the search, they climbed back up the rocky incline to their horses.

âDid you hear what that fellow said?â Frank asked Tico.

âIt was difficult, but I heard most of what he said,â the Mexican boy answered. âHe told the other man that we were scared off by the shooting. They think we have run far from here by now.â

âI wish I was far from here,â Chet mumbled.

Frank suddenly pointed toward the men. âLook!â he blurted. âTheyâre not getting on their horses and leaving. Theyâre just sitting on the groundlâ

âWhat are they up to?â Joe queried.

âWaiting for us to come back,â Chet said ruefully.

âMaybe theyâre not waiting for us at all,â Frank said. âBut whatever the reason, weâll have to stay here till they leave.â

Huddled in their hiding place, the boys spent several agonizing hours under the hot sun. By now their clothes were practically dry. But they were hungry, thirsty, and exhausted by the intense heat. Even after sunset the armed men maintained their vigil.

âAre they going to sit there all night?â Chet grumbled. âI want something to eat!â

âWhen it is very dark,â Tico said, âperhaps we can sneak away without being seen.â

Frank now appeared less anxious to make an immediate getaway. âIâd like to stick around a little while longer and see what those two guys are up to,â he announced. âWe might learn something interesting.â

Another hour had passed when a muffled, rumbling sound drifted in from the sea just beyond the cove.

âWhatâs that?â Chet asked, craning his neck to look out.

âSounds like engines,â Joe said. âGet down, Chet!â

Suddenly a point of light began flashing from the position where the men were sitting.

âTheyâre signaling someone!â Frank observed.

Carefully they turned to look out into the cove. A flashing light pierced the darkness in response.

Gradually the rumbling became louder. Chetâs eyes popped and Joe gasped as the faint outline of a submarine slowly approached the cove!

CHAPTER VII

Night Rendezvous

THE BOYS gazed fascinated as the submarine drew closer to the shore.

âItâs hard to believe,â Frank whispered excitedly, âbut there it islâ

âLeaping lizards!â Chet gasped.

âSo thatâs what those two bandits were waiting for,â said Joe.

All at once there was a burst of activity on the deck. Flashlights, carried by members of the crew as they scurried about, looked like a swarm of agitated fireflies.

âPronto! Pronto!â a crewman barked. Then came an incoherent mumbling of many voices.

Beams of light were directed at the big boulder which Frank and Joe were about to examine when the two armed men had fired at them.

âCome on! Push this thing aside!â shouted a crewman in English. âHurry it up!â

Four husky fellows shoved the rock to one side. Behind it was a large cavity in the incline. Despite their distance from the hole, the boys could clearly see stacks of wooden boxes in the hiding place.

âThe cove is a rendezvous for picking up some sort of supplies,â Joe said.

Frank remarked that it was too dark to see whether the strange symbol was painted on the conning tower, but Joe had an answer for that.

âIâll sneak down to the cove for a closer look.â

âIâll go with you,â Chet offered.

âNo, itâs better if only one of us goes.â

Joe slowly worked his way down through the crevice, then quietly stole along the craggy shore toward the submarine. Crawling on hands and knees, he made his way to a jumble of rocks near the waterâs edge. Joe crouched down and peered over the damp rocks.

âKeep movinâ. Get that stuff aboard!â ordered a bearded, heavy-set man wearing a battered visor cap. It was obvious to Joe that he was not a Mexican. Neither were most of the other crewmen, who carried the wooden boxes to the sub.

Then one of the riflemen approached the bearded man. âQuÃ© tal van las cosasââ the Mexican was saying.

âTalk English!â the other snapped. âYou know I canât speak much Spanish.â

âSentirloâsorry. I do as you wish, senor.â

Loud enough for Joe to hear, the Mexican told of spotting the boys in the cove. âBut we scare âem off. We have no trouble.â

âThatâs what you think!â Joe told himself.

âIt doesnât matter,â the bearded man went on. âWeâve got all the supplies we need and wonât be cominâ back here any more.â

âWhat about me and my amigo?â the Mexican inquired.

âThe boss needs more men back at headquarters. He said you and your friend were to go back with us. Weâd better get goinâ cause the trip takes about twelve hours.â

The crewmen hurried to load all the boxes aboard. The beam of one flashlight swept across the conning tower and Joe squinted intently to get a glimpse.

There it was! The same mysterious symbol!

Joe tingled with excitement. The identical sub, or a sister ship at least, both here and in Barmet Bay!

Satisfied that he had seen and heard enough, he decided to rejoin his companions. As Joe moved, his hand brushed against a loose rock. It splashed into the water loud enough for the crewmen to hear the sound.

âWhat was that?â one man shouted.

Joe froze, waiting anxiously while beams of light crisscrossed the shore.

âSee anything?â another asked.

âNaw. It mustâve been a fish.â

âOkay!â the bearded one shouted. âLetâs get goinâ! Cast off the lines!â

The two riflemen unsaddled their horses and sent them galloping off on their own. Then they quickly boarded the submarine.

Joe gave a sigh of relief and crept off. By the time he returned to his companions, the sub was already on its way out of the cove. Breathlessly, Joe related his findings to the others.

âI wonder where itâs headed,â Chet said.

âThatâs anybodyâs guess,â Joe replied.

âThe bearded guy said it would take twelve hours to get where theyâre going?â Frank queried.

âRight,â Joe replied. âBut in that time the sub could be anywhere from one hundred to more than two hundred miles away, depending on whether the trip is made submerged or on the surface.â

âWhat do you think are in those boxes?â Tico asked.

âHard to tell,â Joe said, shaking his head. âThey appeared to be heavy. Iâd say they contain metal tools, or maybe parts for machinery.â

âThis is one of the craziest situations I ever saw,â Chet declared. âA sub sneaks into a cove at night to pick up a lot of wooden boxes hidden in the rocks. Why not use a regular boat?â

âSecrecy for one thing,â Frank replied. Obvi ously itâs a renegade sub. Andââ

âAnd you can be sure,â Joe interjected, âthat itâs being used for something more than just hauling cargo around.â

âAnd then thereâs the question of Cardillo,â Frank said. âHow does he fit into the picture, if at all?â

âBefore you masterminds begin building up a case,â Chet interrupted, âhow about giving some thought to our food and water problem?â

Joe glanced at the luminous dial of his wrist watch. âItâll be light in a couple of hours. Weâd better wait till then before we go trekking around the countryside.â

âThat is wise,â Tico agreed. âWe would gain little by trying to make our way through the darkness.â

The four boys stretched out in the shelter of some scrubby bushes and fell fast asleep. At the first light of day they awakened and began climbing up the steep, rocky incline. They rested at the top for a moment and peered across the parched and barren plain.

âThere isnât much to eat and drink out there,â Chet muttered.

âThereâs lots of cactus around,â Frank said. âThatâll take care of our water problem.â

âAnd we are sure to find plants which can be eaten,â Tico added, âsuch as acerolo.â

âAcerolo?â Chet blurted.

âThatâs Spanish for hawthorn,â Joe explained. âItâs a plant which bears small red and yellow apples. Theyâre very good.â

As the sun rose higher, the boysâ hunger and thirst grew more intense. Tico led his friends to a cactus plant, removed a fishermanâs knife from his belt, and sliced off the top. He dug out some of the pulp from which he squeezed a small quantity of water.

âYou certainly picked a good one,â Frank remarked with a grin.

As Tico began digging out more pulp for his friends, he saw Chet, a sharp stone in his hand, working on another cactus plant.

âCaramba!â the Mexican youth screamed. âDo not touch that plant! It is muy malo!â

Chet was startled. âItâs what?â

âVery badlâ Tico shouted. âThe liquid is poison!â

âPoison?â Chet muttered nervously. His face turned pale. âWhyâwhy Iâve already drunk some of it!â

CHAPTER VIII

Bullfight

Tico and the Hardys rushed to Chet. He staggered around, as if in great pain, and gripped his chest. âI donât feel too well,â he said in a quavering voice.

âWe must do something!â Joe yelled frantically.

âThe nearest doctor will be miles away!â Frank said.

Suddenly Tico pointed to a figure in the distance. âI see something! I believeâYes, it is a man on a horse!â

âOh, oh!â Joe muttered. âMaybe heâs a friend of those two guys who shot at us.â

âThatâs a chance weâll have to take!â Frank said.

The Hardys and Tico waved their arm wildly and called out to the distant rider. Finally he headed in their direction.

âBuenos dias!â the horseman shouted as he rode up and dismounted. He was short and wiry and had a handsome face.

âNecesitamos un doctor!âWe need a doctor!â cried Tico.

âQuÃ© pasa? What is going on?â the stranger asked.

Tico quickly told the man what Chet had done and pointed to the cactus plant. The man walked over to it, studied the plant for a moment, then he scooped out some of the pulp and squeezed the liquid into his mouth.

âHey! What are you doing?â Joe yelled.

The man grinned. He glanced at the Hardys, then at Chet, who by this time was rolling on the ground. âAmericanos?â he inquired.

âYes!â Frank replied, and added, âYou speak English?â

âI do,â was the calm reply.

Chet moaned and his eyes rolled. âPlease help me!â he pleaded. âJust donât stand there and talk.â

Tico turned excitedly to the horseman. âWhy did you drink from the poison cactus, senor?â

âThe water is good,â the man said. âThe plant looks like a poisonous kind. But it is not.â

They all sighed, and Chet blurted, âAre you sure?â

âI am,â the man answered.

Chet recovered quickly and got to his feet. âIâ I guess I am all right, after all,â he said. âBoyl That was a bad scare! Thank you, SeÃ±orââ

âAlvaro Cortines Garcia,â the horseman announced with a courtly bow.

âHow do you do, SeÃ±or Garcia?â Frank said. He introduced himself and the boys.

âWe never expected to see anyone out here in the desert,â Joe remarked. âYou certainly surprised us.â

âI am returning to my ranchero from the town of El Dorado,â Garcia said. âMy hacienda is about six miles from here, near the village of La Brecha.â

Garcia told the boys that he bred horses and burros on his small ranch. He had gone to El Dorado to close a business deal involving the sale of some of his stock.

âI would like to offer you muchachos the hospitality of my home,â the horseman added. âYou all look very tired.â

The boys did not have to be coaxed. They immediately accepted the offer.

By taking turns riding SeÃ±or Garciaâs horse, the travelers had time to rest their exhausted bodies. Nearly two hours later they arrived at the adobe-walled hacienda. It was set in a green patch of semidesert, surrounded by poplar trees nearly as high as the twirling windmill.

The dusty bovs hastened to a trough of sparkling clear water at the base of the windmill. After gulping handfuls of water, they splashed their arms and faces.

As they finished refreshing themselves, a pretty woman and a good-looking boy of about sixteen came from the house. SeÃ±or Garcia introduced them as his wife and son Alfredo.

Tico and Alfredo began to chatter in Spanish. The visitors were ushered past the corral and inside the cool hacienda. Here SeÃ±ora Garcia asked a maid to set the dining-room table and prepare food for the visitors.

Garcia sat with the hungry boys while they were eating. Presently he said, âWe must give a little fiesta tonight to celebrate my success in El Dorado!â

âBueno!â declared Alfredo. âWe will invite some of our amigos from the village.â His father turned to the boys. âAnd you, muchachos, must stay as my guests.â

âIâm all for that!â Chet exclaimed, beaming. âMuchas gracias!â

After a long nap, the Americans spent the rest of the afternoon watching preparations for the fiesta. They helped set up large wooden tables on the patio. Bananas, oranges, limes, and avocados were heaped on some of the tables. Food that was cooking gave off tantalizing odors.

âThis will be a gastronomic adventure!â Chet exclaimed as he viewed the preparations hungrily.

Joe grinned. âWe might never get Chet to leave this place!â

Guests from the village began coming shortly after sunset. As the festivities got underway, torches were lighted to illuminate the area. One man arrived leading a bull and put it in the corral. Many of the younger villagers swarmed around the enclosure to see it.

âWhatâs going on?â Chet asked Alfredo.

âSome of our amigos like to show their skills as matadors,â he replied.

âBullfighting?â Joe asked.

âThey are not real matadors,â Alfredo explained laughingly. âIt is just a game. The bull does not have sharp horns, and he is not harmed in any way.â

The boys hurried over to the corral and saw that one young man had already leaped into the enclosure. He waved a muleta, a small red cloth draped over a stick, in front of the bull.

âToro! Toro!â shouted the would-be matador.

The animal rushed toward him, but the young man side-stepped gracefully.

âOlÃ©! OlÃ©!â the spectators cheered.

The boys watched the fun for several minutes. Then as Frank and Joe walked back to the tables they suddenly became aware of Chetâs absence. âToro! Toro!â came their chumâs voice from the corral.

âOh, no!â Joe yelled. âDonât tell me Chetâs playing matador!â

As the Hardvs ran back they saw their hefty pal inside the enclosure waving a muleta.

âGet out of there!â Frank shouted. âOr weâll have to carry you out in pieces!â

At that instant the bull rushed toward Chet, who side-stepped. But he lost his footing and fell to the ground. The bull sped on past and turned to make another charge.

Chet scrambled to his feet, dropped the muleta, and began running. The bull raced after him and the spectators cheered.

âHead for the fence!â Frank yelled.

Chet did not hear. Instead, he kept running in circles with the bull in pursuit. Finally he made a dash for the fence and tried to force his way between the wooden slats, but he got stuck!

âWatch out for the bull!â Joe warned.

He flung himself over the fence, picked up the muleta, and attracted the animalâs attention away from the panting Chet. Several spectators leaped into the enclosure to help.

With the bull diverted, Frank and Tico pulled Chet loose. The only damage was a couple of buttons missing from his shirt.

âDo you still want to be a matador?â Frank asked with a frown.

âIâll stick to football,â Chet muttered.

âThat waistline of yours almost got you into real trouble with the fence,â Joe added.

âYes, and now Iâm hungry again,â Chet said. âLetâs have some chow.â

It was after midnight when the fiesta ended. After the villagers had left, the boys and their hosts sat on the patio of the hacienda to chat.

âWe enjoyed the fiesta very much, Senor Garcia,â Frank said.

âGracias,â the man replied. âAnd you are all welcome to stay here as long as you wish.â

âWeâd like to,â Joe said apologetically, âbut we must get back to Mazatlan as soon as possible.â

âIâm sorry you cannot remain longer,â Garcia said. âBut if you must leave, I will help you. There is an autobus which travels to the city along a road about fifteen kilometers east of here. I will furnish you with horses and take you there myself.â

âThank you,â Frank said. âCould we leave in the morning?â

âOf course,â Senor Garcia replied.

âSenor, are you familiar with the Sinaloa coast near the spot where you found us?â Joe queried.

âYes, I travel along it many times on my way to El Dorado,â Garcia answered.

âHave you ever seen a submarine in the area?â Joe continued.

âA submarino?â the man muttered with a quizzical expression on his face. âNo, I have not.â

Frank grinned. âI know it sounds like a strange question, but we have good reasons for asking.â

âI do not think it strange,â Garcia assured the boys. âI am certain the navies of many countries sail into our waters from time to time. Why do you ask?â

âWeâd rather not say at present,â Frank replied. âBut weâre sure the submarine we asked you about does not belong to any navy.â

âThis sub has a mysterious insignia painted on its conning tower,â Joe explained. He leaned down and outlined the symbol in the sand.

SeÃ±or Garcia studied it in the light of the flickering torches. Suddenly he leaped to his feet. âCaramba!â he cried, and an expression of fear spread across his face.

âWhatâs wrong?â Joe asked, startled.

âYou must leave here at once!â the man shouted.

âWhat do you mean?â Frank asked.

âI say you must go!â Garcia demanded. âYou might have brought the curse of the symbol to my home!â

CHAPTER IX

The Trail to Baja

âCURSE of the symbol?â Frank blurted. âWhat do you mean?â

âI do not wish to talk about itlâ Garcia snapped. âYou must all leavelâ

âBut you canât just order us out into the desert in the middle of the night,â Joe said angrily.

At that moment Garciaâs wife intervened. She pleaded with her husband to let the boys stay until morning and he reluctantly agreed.

The four companions were led to a jacal, a hut, which contained several empty bunks. Chet and Tico dozed off immediately, but Frank and Joe remained awake for some time discussing Garciaâs strange behavior.

âWhat could be bothering him?â Joe questioned. âHe looked scared out of his wits when I outlined the symbol.â

âObviously it has some connection with a fright heâs had,â Frank surmised. âI wish we could get him to tell us about it.â

âFrom his reaction, Iâd say our chances are nil,â Joe said.

In the morning the Hardys were relieved to find that Senor Garcia had calmed down considerably. He even invited them and their friends to have breakfast with him.

âI must apologize for my behavior last night,â he said. âAs I promised, I will guide you to the road where you can board the autobus to Mazatlan.â

After eating, Garcia and the boys started out on their journey. It was early afternoon when they arrived at their destination, a narrow, unpaved road stretching north and south through a lonely expanse of desert country.

âOnly one autobus a day travels this road to Mazatlan,â Garcia explained. âIt should pass this way within the next hour or two.â

While they waited, Frank decided to take another chance at questioning their host.

âSeÃ±or, I donât want to upset you again,â he said, âbut is there nothing you can tell us about the symbol?â

Garcia glared. âNo! There is nothing!â

Then, without mentioning Marcheta by name, Frank described how the engineerâs son had been kidnapped. âHe is about your own sonâs age. And we suspect that thereâs some connection between the symbol and the kidnapping. If you tell us what you know, it may solve this mystery.â

Garcia did not reply. He stared blankly into space for a long moment, then said, âI am a coward for not speaking. Perhaps I should have gone directly to the authorities.â

âWhat do you mean?â Joe queried.

âYou must first promise that you will not reveal who told you what I am about to say,â the rancher declared.

The Hardys nodded.

âSeveral weeks ago,â Garcia continued, âI went to visit my cousin who lives in the village of Montaraz in Baja. But when I arrived there I was told that he had mysteriously disappeared the day before. Painted on the door of his hacienda was the symbol you described to me.â

âDid you speak to any of the villagers about your cousinâs disappearance?â Frank asked.

âYes, I tried to. But they were all badly frightened and refused to speak.â

âWhat were they frightened about?â Joe asked.

âI learned that five other men in the village had also vanished in the same way,â Garcia answered. âAnd the symbol was painted on the doors of their haciendas!â

âWhy didnât you notify the police?â Frank questioned.

âI intended to do so, of course,â the man answered. âBut there are no police in Montaraz. I therefore planned to go to the city of Ensenada the following day to notify the authorities. I went to my cousinâs to spend the night and the next morning found a message under the door.â

âWhat did it say?â Tico asked.

âIt warned me that if I talked to the authorities,â Garcia said nervously, âthe curse of the symbol would find me wherever I go!â

âLeaping lizards!â Chet exclaimed.

âI am not a cowardly man,â the rancher continued, âand it is not for myself that I am frightened. I fear for my family!â

âWe understand,â Frank said sympathetically.

Soon the bus arrived. The boys thanked SeÃ±or Garcia for his hospitality, then boarded the bus for the bumpy, dusty ride back to Mazatlan. When they reached their hotel, the desk clerk handed the Hardys a telephone message. It read:

Remaining with our friend for a while. Will contact you later. F.H.

âDadâs staying with Senor Marcheta in Mexico City for a while,â Frank said as he handed his brother the message.

âI hope heâs not running into trouble,â Joe replied.

âI donât think so,â Frank said. âHeâs probably hoping to worm more information out of Marcheta.â

âWhen do we eat?â Chet interrupted.

Frank grinned. âTell you what. The hotel has room service. Why donât we have supper in our suite?â

âGood idea,â Joe agreed. He turned to Tico. âAnd you must join us as our guest.â

âThank you,â the Mexican youth answered. âI would like to very much.â

The boys had a hearty dinner, after which Frank unfolded an air chart of Mexico.

âHereâs Montaraz, the village where Senor Garciaâs cousin disappeared,â Joe said eagerly. He inspected the map more closely. âSure is rugged country. The desert area covers about six thousand square miles I understand.â

âAnd many of the mountains to the east are comparatively unexplored,â Tico added. âOne could easily disappear in that area and, perhaps, never be found.â

Frank took out a pair of measuring dividers and calculated the distance to the village. âHm! We might be on to something,â he said, and thought for a moment. âLetâs assume that the sub we saw in the cove maintained an average speed of twelve to fifteen knots. In twelve hours it would reach a point on the east coast of Baja not too many miles from Montaraz.â

âWow!â Chet exclaimed. âThis could be an important lead!â

âAt least itâs worth checking out,â Frank concluded. âWhy donât we go there and see what we can find?â

âToo bad Dadâs plane is in Mexico City,â Joe remarked. âWe could fly there in two hours.â

âThere arenât any airports near the village,â his brother observed as he examined the chart. âAnyway, it would be less conspicuous if we went by boat.â

âMaybe we can rent one,â Joe suggested.

âI can be of help to you,â Tico put in. âA friend of my fatherâs has a boat rental service. He can provide you with a small cabin boat. But you must let me come with you. I have some knowledge of the waters in the area.â

âItâs a deal!â said Frank.

Early the following morning the boys prepared for their trip. Before departing, the Hardys left a message for their father with the desk clerk. It read:

Gone Fishing. Wish us luck. We should be back in two or three days.

Tico proved to be an excellent seaman and navigator, and they made the journey in record time. As the craft neared its destination, the boys scanned the craggy coastline for a place to land.

Joe examined a map. âMontaraz is about six miles inland from our present position. Weâd better find a place to tie up around here.â

Just then Chet pointed toward the shore. âI see a little hut! And a small boatâs tied up to a dock in front of it!â

âThereâs a man, too,â Joe said.

The boys headed toward the spot. As they drew nearer, they saw that the dock was in a run-down condition. The hut was also decrepit, and appeared undecided as to which way it was going to fall.

âBuenas dias, amigo!â Frank shouted to the elderly man who was resting against a cirio tree.

The old fellow raised the brim of his sombrero and peered at his visitors.

âDo you speak English?â Joe called out.

âHe does not understand,â Tico observed. âI will talk to him.â

The Mexican youth chatted with the man for several minutes. He then returned to his friends. âThe old man lives here by himself,â Tico ex plained. âHe says we may use his dock for eighty pesos a day.â

âDid you ask him the way to Montaraz?â Frank inquired.

âYes. There is a trail behind his hut which will take us to a road leading to the village. But I am afraid we will have to walk, since there is no transportation available.â

âOh, no!â Chet bellowed.

The boys started off on their journey, taking with them an emergency kit of camping equipment, food, and water. It was almost sunset when they reached Montaraz. The village, consisting of about sixty adobe-walled houses, appeared quiet and peaceful.

Most of the structures surrounded a wide, circular piece of ground which served as the plaza. On the south side of the plaza was a sun-baked mud-brick building that served as a cantina and general store. There were no villagers in sight.

âWhere is everybody?â Joe queried.

âI donât know,â Frank muttered with a puzzled expression.

âPerhaps we will find someone in the cantina,â Tico suggested.

The boys strolled over to the structure and found two of the villagers inside. They were middle-aged men and wore sombreros and colorful sarapes. Tico conversed with them in Spanish. Then he turned to the Hardys and Chet.

âThe men say that the people of their village all remain in their haciendas from sunset to sunrise,â the Mexican youth said. âIt is because they fear Pavuralâ

âPavura?â Joe questioned. âWhatâs that?â

âIt means âterror,â â Tico said. âThe men also say that we should leave because strangers are not welcome here. Anyway, there is no place for us to stay.â

âThatâs hospitality for you,â Chet grumbled.

Tico tried to question the villagers further, but he and the other boys were ordered out of the cantina.

âItâs a cinch weâre not going back to Mazatlan without trying to get some information,â Frank said angrily.

âWhy donât we make camp for the night,â Joe suggested. âMaybe weâll have better luck in the morning.â

The boys pitched their tent on the outskirts of the village, then prepared supper from a variety of canned foods included in the camping kit. Soon after eating, they all fell asleep. The following morning the young sleuths got ready to return to the village.

âChet,â said Frank, âyou stay here and break camp. Tico, Joe, and I will go in town and see what we can find out.â

Several villagers were walking about when the boys arrived in the plaza. It was impossible, however, to get any of the people to talk.

âWhatever, or whoever, this Pavura is,â Joe remarked, âit sure has these villagers scared.â

As they continued walking, Frank suddenly pointed to one of the houses. âLook!â he declared. âThat must be the home of one of the villagers SeÃ±or Garcia told us disappeared. Thereâs the symbol painted on its doorlâ

They walked forward to examine the door more closely when a stocky Mexican man seemed to appear from nowhere and blocked their path.

âWho are you?â Joe demanded.

The man did not reply. He drew a large, gleaming machete from his belt and raised it threateningly !

CHAPTER X

A Villager Speaks!

âVÃ¡yase ustedes!âLeave here!â the man with the knife shouted.

âPor quÃ©?âWhy?â Frank retorted.

The Mexican pointed to the symbol painted on the door. He then let go a volley of words so rapid that even Tico had difficulty understanding him.

âWhatâs bothering him?â

âHe says that the presence of strangers in the village will bring Pavura down upon them,â Tico explained. âHe wants us to leave at once.â

The man wielded the machete menacingly.

âLetâs not push the issue,â Frank advised. âIt would only make things more difficult for us if we got involved in any trouble.â

The man glared at the boys as they walked off.

âI donât think weâre going to get any information out of these people,â Joe concluded, disappointed.

âBut there must be at least one villager with enough courage to talk,â Frank said.

âGarcia said there arenât any policemen here,â Joe commented. âHow do they keep law and order?â

âUsually the elders of a village appoint a man to be, what you call in your country, a sheriff,â Tico explained.

âThen why donât we find out who he is and ask him some questions?â Joe suggested.

âGood idea!â his brother replied.

At the Hardysâ suggestion, Tico approached an old man they spotted walking across the plaza. After a brief conversation, the Mexican youth returned to his friends.

âHe says the man we seek is Senor Miguel Santos,â Tico said. âBut luck is not with us, for Senor Santos is one of the villagers who disappeared. Only his wife remains at home.â

âWhere is it?â Frank asked.

âOn the south side of the plaza, the one with the strange symbol painted on its door.â

The boys quickly located the house. They examined the painted symbol for a moment, then Frank rapped on the door. It creaked open, revealing a thin, handsome woman. Her face was taut and pale.

âSenora Santos?â Frank asked.

âSi,â she responded with a bewildered expression.

The boys introduced themselves, and after stating their business, asked the woman if she would help them.

SeÃ±ora Santos seemed eager to discuss her husbandâs disappearance. She announced, much to the delight of the Hardys, that she spoke a little English.

âMy husband and I once live in Mexicali,â she said, forcing a smile. âWe have much opportunity to learn your language there.â

Senora Santos invited the boys inside and asked them to be seated in the tall wicker chairs that were scattered about the room.

âWhat can you tell us about your husbandâs disappearance?â Frank questioned.

âI know very little,â Senora Santos informed her visitors regretfully. âOne night he returns from a hunting trip and tells me he see something strange in the mountains.â

âWhat sort of thing?â Joe asked.

âHe says that he see a group of men walking through the mountains,â she explained. âMany were dressed like the Aztec warriors of old days. They were all chanting mysterious music.â

âDid your husband talk to any of them?â Frank inquired.

âNo,â the woman replied. âBut then some of the men see my husband. They chase him, but my Miguel escapes.â

âWhen did you last see your husband?â Joe queried.

âThe night he return from the mountains,â she answered. âAfter eating his supper, he went to the cantina to tell his amigos about the men he see.â Her eyes began to fill with tears. âMy Miguel never come back. In the morning I find mysterious symbol painted on the door.â

âWhat about the other villagers who vanished?â Frank asked.

âThey are my husbandâs amigos,â the woman said. âEach of them go to search for Miguel and never return. The doors of their houses are also marked with the symbol.â

âAnd now the people of the village are too scared to do anything about it,â Frank commented.

âThat is right,â Senora Santos agreed. âI should have notified the authorities myself, but I do not wish to endanger the others in the village. Then when you boys ask me to help, I decide not to remain silent any longer. I know you try to help. I trust you.â

The boys thanked the seÃ±ora and returned to their camp, where Chet had already finished packing the equipment. âItâs about time you masterminds got back,â he blurted. âDid you pick up any information?â

The Hardys told about Senora Santos. âAs I see it,â Frank said, âthe mystery is somehow linked to those men SeÃ±or Santos spotted in the mountains. Itâs a slim lead, but Iâm all for going there and having a look.â

âIâm game,â Joe announced.

Frank turned to Chet and Tico. âOf course itâs not fair of us to ask you fellows to come along on such a dangerous mission. If you want to ...â

âWhat!â Chet exclaimed. âMe stay here without you? And whoâs going to keep you out of trouble? Count me in!â

âMe too!â Tico chimed in.

âGood,â Frank said with a grin. âBut well need more supplies.â

âMaybe we can buy them at the general store in the village,â Joe suggested. âLetâs hope theyâll let us in.â

âIf we are going into the mountains,â Tico said, âI would recommend we use burros.â

âHold on!â Joe commanded. âWe might not have enough money with us to swing it.â

âPerhaps we can pay in travelerâs checks,â Frank remarked jokingly.

The Hardys quickly examined their funds. Chet and Tico offered to chip in what cash they had.

âThat should be more than enough to buy what we need,â the Mexican youth observed. âBurros are not expensive here.â

The boys returned to the village and headed directly for the store. Much to their surprise, the proprietor seemed too eager to assist them. He not only sold them the supplies they needed, but he also arranged for the purchase of burros at a reasonable price.

âThe proprietor certainly went out of his way to help us,â Joe commented.

âNaturally,â Frank replied. âHe and the villagers are glad to get rid of us.â

Shortly the boys were off on their journey toward the distant mountains. As they jogged along, the terrain became more difficult to travel.

âThis must be the slowest form of transportation in the world,â Chet said as he tried to get his burro to move faster.

âThese animals are slow,â Tico explained. âBut they are reliable and sure-footed.â

The air became cooler as the riders moved higher into the mountains. Near sunset, Frank suggested that they stop and make camp.

âThereâs a flat piece of ground over there,â Joe observed.

It was dark by the time they had pitched their tent and gathered firewood to cook supper.

Chet struck a match and was about to light the tinder when Frank suddenly hissed, âPut that out!â

âWhatâs the matter?â Chet asked, flicking out the glow.

âI see a campfire!â

âWhere?â Joe asked.

The proprietor seemed too eager to sell them supplies

âOn the other side of that gully. About half a mile away!â

âMaybe itâs a party of hunters,â Tico suggested. âThere are mule deer, antelope, and mountain lions in this area.â

âCould be,â Frank answered cautiously. âThen again, it might not be. Weâll have to check it out. Chet, you and Tico stay here and guard the camp. And donât light a fire. Weâll be back as soon as we can.â

âBe careful,â Tico warned. âThe ground is dangerous.â

Frank and Joe started off, moving slowly across the craggy terrain. In places the ground was gouged with narrow crevices and holes. They worked their way up a slope, then across a level stretch covered with tangled brush. Finally they dropped to hands and knees and crawled the rest of the way.

âThereâs the campfire in that clearing just ahead,â Joe whispered. âKeep your head down!â

As the excited boys crept closer, a weird sound of chanting voices drifted to their ears.

CHAPTER XI

Mountain Pursuit

THE SOUND sent a chill through the Hardys! Was this the strange music Santos had told his wife about?

More cautious than ever, Frank and Joe crawled forward on elbows and stomachs. In a few minutes they had the campfire in sight. Seated around it were eight men. Two, who wore sombreros and sarapes, were not Indians, but the others appeared to be Indians. Their colorful garb looked like that worn by ancient Aztec tribes.

Beyond the fire and barely perceptible in its glow stood an Indian, with a rifle nestled in the crook of his arm. He seemed to be guarding the prone figure of a man, wrapped in a blanket and lying on the ground beside him.

Suddenly the two men wearing the sombreros got to their feet and began walking toward the spot where the boys were hiding. Quickly Frank and Joe moved behind a clump of brush and waited, their hearts pounding.

The two men came to a stop within a few feet of them. âNo me queda bien,â one said.

Fearing they might have been discovered, the Hardys poised themselves for action.

âShâspeak English, amigo,â the manâs companion ordered. âIf the others hear us, they will not know what we talk about.â

âI do not care,â the first man replied defiantly. âPavura does not frighten me. He has broken his promise. We were to be paid for our work. Yet I have not seen a single peso.â

The boys gave inward sighs of relief! The men were unaware of their presence!

âLet us speak to Pavura when we return with the American,â said the second man. âWe will demand payment!â

The two men returned to the campfire, and the Hardys crept back to their own camp and reported what they had learned.

âYou say they have an American with them?â Chet said.

âYes,â Frank replied. âHe must be the one we spotted lying on the ground.â

âI wonder who he is,â Chet said.

âWill you try to rescue him?â Tico inquired.

âNot right away,â Frank replied. âFirst weâre going to follow those men and see where theyâre going.â

âIn rough country like this?â Chet countered. âImpossible.â

âI can be of help to you,â Tico said. âMy grandfather was Indian. As a young child he taught me much about tracking. I am sure I can follow their trail.â

Frank outlined a plan. He, Joe, and Tico would go to keep an eye on the men. When their quarry made ready to leave, Joe would return to their own camp and tell Chet.

âTico and I will mark a clear trail for you two as we go along,â Frank told his brother. âYou can then follow us at a safe distance with our burros and equipment.â

âSounds like a workable plan to me,â Joe commented. âBy the way, I noticed those fellows didnât have any horses or burros. They must be traveling on foot.â

âThatâll make it a lot easier for us,â Frank concluded.

Since the situation prevented them from lighting a fire, the boys had a cold supper of canned meat and vegetables. Then Frank started back across the gully with his brother and Tico. When they spotted the encampment, they saw that the men had gone to sleep. One Indian remained awake to stand guard.

âWe have a long night ahead of us,â Frank said in a hushed voice. âLetâs rotate a watch. Iâll take the first shift. You two get some sleep.â

At dawn the camp suddenly became alive with men scurrying about. Tico, who was the last to keep watch, shook his companions awake.

âI believe the men prepare to leave,â he whispered excitedly.

Frank and Joe spied on the activity. One of the two men, wearing a sombrero and sarape, walked over to the prone figure wrapped in a blanket.

âI think you have enough siesta, senor,â the man snapped sarcastically. âWe go now.â He pulled off the blanket to reveal a thin, gray-haired bespectacled man, tied hand and foot.

Elmer Tremmer! The Hardys gasped at sight of the pathetic figure, whom they recognized from a photograph in their fatherâs dossier.

âWhy did you tie me up?â Tremmer complained timidly. âI wasnât trying to run away!â

The man with the sombrero bent down and untied him. âI take no chances. Pavura would not like it if we return without you.â He then pulled his prisoner to his feet.

According to plan, Joe hurried off to rejoin Chet. Frank and Tico watched as their quarry broke camp and headed in a direction that would take them deeper into the mountains.

âWeâll give them a head start,â Frank remarked.

Tico proved to be an excellent tracker. He quickly picked up the trail and followed it with ease. Frank marked their course by forming directional arrows on the ground with stones and twigs.

It was just about midday when Tico suddenly came to a halt. âLook!â he said in a low voice. âThere are the men!â

Just ahead Frank saw their quarry. The men were seated on the ground. One Indian was distributing dried maize among them.

âTheyâve stopped to eat,â Frank said. âWeâd better do the same, Tico.â

The boys pulled several cans of rations from their pockets and ate quickly, then waited until the men set off again. It was almost dark before Frank and Tico had their quarry in sight once more.

The men were assembled in a clearing surrounded by steep, rugged hills. At the base of one hill was a large boulder which several Indians shoved aside. Behind it was the entrance to a cave. The men entered, pushing Tremmer ahead of them. Several Indians remained outside to replace the boulder and stand guard.

âThis is their hideout!â Frank said excitedly. âLetâs backtrack and meet Joe and Chet before they reach this spot. The burros are likely to make noise and give us away.â

Returning along the trail, the two boys traveled nearly a mile before they met the others.

âLeaping lizards!â Joe exclaimed as his brother told where the trail had led. âYou say they went into a cave?â

âThatâs right,â Frank answered. âLetâs recon noiter the area in the morning. Maybe we can find out what theyâre up to.â

The boys made camp close by and ate supper. All slept soundly. Shortly before dawn, Frank awakened and aroused the others.

âWeâll go back to the place where Tico and I spotted the cave,â he said. âItâll be better if we go before daylight. Also, one of us will have to stay here and guard the camp and burros.â

âI guess Iâm elected again,â Chet grumbled.

Tico observed his expression of disappointment. âI shall stay here,â he announced with a smile.

The Hardys started out with Chet along the marked trail. When they arrived at their destination, they selected a hiding place from where they could view the cave. Within the hour the sun began to appear above the crest of the mountains.

âThere are the Indian guards,â Frank whispered as light spilled into the clearing.

âTheyâre all asleep,â Joe observed.

âThose guys donât seem to be taking their jobs seriously,â Chet added.

âObviously they donât expect outsiders to be roaming around these mountains,â Frank said.

Finally the guards began to awaken. They scrambled to their feet and rolled aside the boulder covering the cave entrance. Soon, about forty Indians emerged and hurried off as if on an urgent mission.

âLook at all those men,â Joe hissed. âWhere could they be headed?â

The boys watched as the guards went into the cave and, seconds later, reappeared with Tremmer. They marched off after the others, leaving only one man behind. The Indian found a shady spot at the edge of the clearing and promptly went to sleep again.

âNowâs our chance to take a look inside,â Joe whispered.

The boys crept from their hiding place and across the clearing. They froze in their tracks when the sleeping Indian grunted, but he did not wake up.

When they reached the cave entrance, Frank whispered, âBe careful. There might still be someone in there.â

The searchers crept cautiously through the entrance. Inside, they found a spacious cavern. Through the gloom, faintly illuminated by several nearly burned-out torches, the boys saw that the cave was empty.

Joe suddenly grasped his brotherâs arm. âLook! In the center of the floor ! Itâs the sym bol!â

They all stared in awe at a large stone altar. On it was carved a cluster of branches or faggots. And mounted on top was a stone inscribed with the letter P.

Quietly Joe climbed up the side of the altar. At the top, he saw that a deep, circular channel had been cut into the stone. Charred bits of wood indicated that the channel was used to hold a fire.

âHoly crow!â he said to himself. âI wonder if this is some kind of cult.â

Frank, meanwhile, in searching for clues, came upon a large section of damaged stone at the base of the altar. The broken fragment had been set back loosely into place. He pulled it away slightly and peered in through the opening.

The lower portion of the altar proved to be hollow.

âHey, fellows!â Frank whispered. âTake a look at this.â

âCaramba!â Chet exclaimed. âAnd see this, Frank.â He moved toward the far corner of the cave. In the shadows was a stack of empty wooden crates marked MACHINERY.

âThese look like the same type of boxes we saw being loaded aboard the submarine in the cove,â Frank said.

Nearby were a number of small, wooden barrels with the word muestra painted on their sides.

âMuestra!â Joe remarked. âThat means âsampleâ in Spanish, doesnât it?â

Frank nodded, then sniffed at one of the barrels. âSmells like crude oil to me,â he muttered.

âWhat a discovery!â said Chet. âCome on. Letâs look around some more.â

At the rear of the cave, Frank found a cavity in the wall. Its opening was covered by a door of metal bars.

âLooks like a prison cell,â said Joe.

At that moment Frank spotted a small fragment of paper on the floor. He picked it up. There was a single line of print:

The practicability of the draco ...

âThis must have been part of a page from a magazine,â he said, handing the fragment to his brother.

Joe examined it. âYou might be right,â he agreed. âToo bad we donât have the rest of it.â

âIâd like to see the complete spelling of the last word which begins with draco,â Frank commented. âSomething about it rings a small bell! Iâmââ

âListen!â Chet interrupted. âI hear something!â

The boys remained perfectly quiet for a moment.

âI hear it too!â Joe said finally. âMen talking!â

The three darted toward the entrance but halted abruptly when they saw the shadows of three men on the ground outside.

âOh, oh!â Frank whispered. âIt must be the guards!â

âAnd theyâre armed,â Joe added. âIt would be too risky to try and make a break for it now.â

âBut we canât stay here!â Chet whispered nervously. âThat crowd of Indians might come back any time now.â

Chetâs fears were warranted. Soon many men could be heard approaching the cave entrance. The boys frantically searched for a place to hide.

âQuick!â Frank commanded, remembering the altar. âFollow me!â He pulled aside the broken fragment of stone at its base. âInside! Hurry!â

The boys squeezed through the opening and into the hollow portion of the altar. A split second later the Indians poured into the cave.

âFuego!â one of them shouted. âFuego por Pavura!â

The boys were horror-stricken. The Indians were about to build a fire on top of the altar!

CHAPTER XII

The Search

âWEâLL be roasted alive!â Chet quavered.

âQuiet,â Joe warned, nudging Chet with his elbow.

Frank fully realized their desperate situation. If they left their hiding placeâcapture! Yet to remainâdestruction!

The fire was started, and the boys waited tensely for the temperature to rise. But much to their surprise, the heat was not intolerable.

âOf course!â Frank said to himself. âThe altar is made out of volcanic rock. It is radiating the heat of the fire too rapidly to get very hot itself!â

From outside came the same kind of weird chanting they had heard the previous night.

âThey must be performing some kind of ceremony,â Joe whispered into his brotherâs ear.

Suddenly the chanting stopped.

âPavura! Pavura!â the Indians shouted in unison.

The deep voice of a man, obviously that of their leader, addressed them in Spanish.

âWhatâs he saying?â Chet hissed.

âI can only pick up a few words,â Frank whispered. âHe thanks them for their work, and says theyâll be rewarded soon.â

After the ceremony the Indians left. Their footfalls faded away. Frank was about to push the broken stone aside when he suddenly stopped at the muffled voices of two men speaking in English.

âWhy am I being treated like a prisoner?â one man asked.

âYou tried to run away, Senor Tremmer,â the other replied. âPerhaps you go to the authorities. I do not like that.â

âYouâre wrong, Vincenzo! I didnât try to run away! Didnât I come to Mexico with you of my own free will? I just went out for a walk and got lost.â

âOdd, then,â Vincenzo replied, âthat my men find you more than a dayâs journey from here. I do not believe you. However, I will give you one more chance. But if you run away again, I shall send my men after you with orders not to bring you back.â

âDonât threaten me, Vincenzolâ

âAh, but I will. And do not speak my name in the presence of my men. To them I am known only as Pavura!â

Vincenzo and Pavura! One and the same! The boys quivered with excitement. And Vincenzo was the leader of the Indians, who worshiped him.

More footsteps. Then silence.

âTheyâve gone!â Joe whispered.

The boys cautiously crawled from their hiding place, and edged toward the cave exit. Seeing no sign of the guards, they dashed across the clearing and headed back to their own camp. After eating and taking a short rest, the young detectives mulled over the situation and discussed a new plan.

âTico, you take one of the burros and go back to Montaraz,â Frank instructed him. âAsk Senora Santos to help you get in touch with the authorities. Tell them what weâve found out.â

âSi, I will do as you say,â the Mexican youth promised. âBut what do you plan to do?â

âChet will guard the camp, while Joe and I re connoiter the area,â Frank explained. âWeâd like to find out what those Indians are up to.â

After Tico departed for the village, the Hardys began a systematic search of the surrounding territory. They carefully threaded their way across the difficult, lunar-like terrain.

âWhen the Indians leave the cave,â Joe said, pointing off to his right, âthey go in that direction.â

âRight,â Frank agreed. âBut letâs stay close to this ridge. The rocks will give us good cover.â

Nearly an hour had passed before the boys heard sounds of activity somewhere ahead of them.

âWhatâs that?â Joe asked curiously.

âSounds like men digging,â Frank replied.

The Hardys continued on slowly. Soon they came upon a startling scene. In a small clearing ahead, Indians were working busily. Some were digging with picks and shovels. Others carried heavy wooden crates.

âLooks like some kind of mining operation,â Frank said in a hushed voice.

The boys crept ahead for a closer look. They saw several Mexicans, not dressed as Indians, assembling various pieces of machinery. Nearby was a narrow-gauge railroad that stretched out of sight down an incline to the east. Resting on the track was an unusual-looking vehicle. It was an elongated wooden platform with sides that angled outwards and was set on eight small rail road-type wheels.

âWhatâs that?â Joe blurted.

âIâve never seen anything like it used in mining,â Frank whispered. âIt must be ninety feet long.â

âAnd about six feet wide,â Joe added.

âLetâs work our way around to the other side of the clearing. Be careful. We donât want to run into any of these guys.â

The boys edged their way along, studying the scene with increasing interest. Then Frank began to sniff the air. âI smell crude oil.â

âI do, too,â Joe said.

Just then the Hardys heard a man shout from somewhere behind them. âFareâHalt!â

The boys whirled to see an Indian with a rifle standing at the top of a knoll.

âWeâve been spotted!â Joe gasped.

A shot rang out, and the Hardys ran. More shots. A bullet ricocheted off a rock close by.

âHead for the ridge!â Frank cried.

By now the Indians in the clearing had dropped their tools and were racing off in pursuit of the boys.

Joe stumbled and fell. Frank stopped and yanked him to his feet. âAre you all right?â

âYesâIâm okay! Letâs keep going!â

In the next instant the Hardys were startled to see several more Indians blocking their path to the ridge.

âThis way!â Joe shouted as he started down a slope to the right.

The boys zigzagged through the craggy terrain. After a grueling race, they gradually outdistanced their pursuers.

âWeâre losing them!â Frank shouted.

Despite their exhaustion the boys forced themselves to maintain their rapid pace. But they had traveled only a little farther when they suddenly came to a halt.

âIt canât be!â Joe yelled, pointing directly ahead.

There was the clearing where they had spotted, the Indians.

The youths had run in a complete circle. Soon shouts began to come from all sides.

âWeâre surrounded!â Joe cried out in dismay.

CHAPTER XIII

A Charging Donkey

As THE Hardys ran toward the clearing, Joe moaned, âWeâre trapped!â

âHold on!â Frank shouted. âWe might have one chanceâthat railroad car! Maybe we can ride it out of here!â

Amid shots from their pursuers, the Hardys darted to the odd vehicle, which was anchored by two heavy chains. They quickly unfastened the car and pushed it down the slope with all the strength that they could muster. Once it had picked up momentum, the boys leaped aboard.

Bam! Bam!

Frank and Joe ducked as bullets thudded into the sides of the wooden platform. The car gained speed. Indians appeared along the sides of the track, shouting and waving their arms, but they were helpless to do anything. Soon the pursuers were left far behind.

The boys raised their heads to look about. They were traveling downhill at breakneck speed.

âNow how do we get off this thing?â Frank shouted. âWeâre moving too fast to jump!â

Joe pointed ahead and gasped. âLook!â Farther down the slope the track came to an abrupt end. Fifty feet from there lay a stack of rusting rails, directly astride the carâs path.

âThere must be a brake system somewhere on this!â Frank said.

The ground rushed by in a blur as the boys frantically searched for a way to stop the car. Joe stumbled to the rear and looked over the side. Spotting a long metal lever just within reach, he grabbed it and pulled upward with all his strength. The rear wheels of the car locked, throwing up a shower of sparks.

âI found it!â he exclaimed.

Frank discovered a similar lever on the right side and yanked up on it hard. The center wheels of the car locked, also producing a geyser of sparks.

Anxious moments followed as the car continued to coast down the slope, but slower and slower. Finally it came to a stop a few feet short of the trackâs end.

âWhewlâ Joe sighed. âThat was close.â

Frank mopped his brow. âIf we hadnât found those brake levers, weâd have ended up in little pieces.â

The boys leaped out and trotted over to the stack of rails.

âApparently theyâre still in the process of building this road,â Joe observed. âI wonder where the track will lead when itâs finished.â

âThatâs something weâll try to figure out later,â Frank said. âRight now, weâd better get out of here. Those Indians are probably on their way!â

They set off at a brisk pace, and after about a mile, stopped to rest.

âOur camp shouldnât be too far from here,â Frank commented. He took a compass from his pocket to estimate the direction they should head. âWeâd better get back before Chet starts worrying.â

When they reached their camp the Hardys found Chet propped up against a rock, whittling a stick of wood. He appeared dejected.

âIâm bored,â muttered Chet. âWhen are you going to let me in on some action? Iâm tired of playing baby sitter to a bunch of burros,â he complained.

Joe laughed. âWe want to keep all you donkeys together.â

Moving like a charging lineman, Chet dropped his whittling and tackled Joe below the knees. The blond boy hit the ground with a thud, then rose grinning.

âI guess I asked for that,â he admitted ruefully, and added, âChet, did you ever think of playing pro football?â

The horseplay lifted Chetâs spirits, and he listened eagerly as the Hardys told him about the runaway rail car. Then he opened some cans of food and they ate, seated on the ground.

âI hope Tico had luck contacting the authorities,â Joe remarked.

âLetâs keep our fingers crossed,â said Frank. âMeanwhile, weâll stay here and keep an eye on the Indians.â

It was late afternoon when the Hardys crept back to the spot from where they could view the cave.

âOh, oh! They have more guards,â Joe observed.

âJust a precaution,â Frank surmised. âVincenzo isnât taking any chances after his men reported a couple of outsiders in the vicinity.â

âOne thing is sure,â Joe added, âweâre safe here. This is the last place theyâd expect to find us.â

As darkness came on, the Hardys saw Tremmer emerge from the cave. He strolled casually around the edge of the clearing and sat down on a boulder.

Frank leaned close to his brother. âIâm going to crawl down there and try to speak to him.â

âBut he might give you away.â

âI have a feeling he wonât,â Frank said. âBut if anything does happen to me, get back to our camp and wait for Tico to return.â

âOkay. Be careful!â

Frank crept cautiously toward where Trem mer was seated. He maneuvered himself into a position directly behind the boulder, checked to see if the guards were at a safe distance, then called out in a low voice.

âElmer Tremmer!â

âWhoâwhoâs that?â stammered the startled bookkeeper.

âShâIâm a friend,â Frank assured him.

âQuÃ© pasa?âWhat is going on?â one of the guards shouted.

âErâerânothing! Nothing at all!â Tremmer answered, turning his head away from Frank.

The guard appeared satisfied and resumed his conversation with a companion.

âWho are you?â the bookkeeper whispered excitedly.

âMy name is Frank Hardy.â

âHardy? The Bayport detective?â

âIâm his son. My brother and I are here to help you.â

âHelp me? How?â

âTo escape.â

Tremmer shifted uneasily. âNo! I donât want to escapelâ he said in a frightened voice.

âIf youâre afraid to go back to the States,â Frank whispered, âdonât be. The authorities only want you to testify as a witness in the stock-fraud case.â

âBut Vincenzo told me Iâll go to jail. I ...â

âWho is this man Vincenzo?â the young detective queried.

âHeâs a very dangerous man,â the bookkeeper warned. âHe leads these Indians under the name Pavura. Theyâre very superstitious and think heâs some kind of god. When I first met him, he used the alias Cardillo.â

The young detective was startled. Another alias! So Cardillo, Pavura, and Vincenzo were really one! Frank pushed himself closer to the boulder.

âWhat is he using the Indians for, Mr. Tremmer?â

âIâI canât tell you. And Iâm not going to try to escape again. If Vincenzo caught me ...â His words trailed off. He got up and walked toward the cave.

Greatly disappointed, Frank rejoined Joe.

âAny luck?â Joe whispered.

âIâm afraid not,â Frank answered, then told him about the conversation with Tremmer.

âHe might go straight to Vincenzo and warn him about us,â Joe said worriedly.

âI donât think he will. My guess is that Vincenzo scared him into coming to Mexico. He probably told Tremmer heâd go to jail with the rest of them if they were caught.â

âWhile all the time he just wanted to get Tremmer out of the way so he couldnât testify,â Joe declared.

âRight!â

âDo you think heâll stick with the gang?â

âIâve given Tremmer reason to doubt Vincenzo,â Frank said. âIf he realizes heâs only wanted as a witness, he might come over to our side.â

The Hardys decided to return to their camp. It was dark when they arrived.

âFunny,â Frank murmured. âIâm sure this is where we had our campsite.â

The boys exchanged puzzled glances.

âChet!â Frank called in a subdued voice. âChet!â No response.

âWhere are you?â Joe called louder.

âThis has got to be the right spot,â Frank said in alarm. He pulled a pencil flashlight from his pocket and played its beam on the ground. âLook!â He quickly bent over and picked up a small object. âThis is the stick Chet was whittling!â

âBut thereâs no sign of him or the burros and equipment!â

Joe spotted footprints in the soft dirt. Their pattern was scrambled, indicating that a struggle must have taken place.

Meanwhile, Frank made another discovery. Revealed in the bright, narrow beam of his light was a small heap of ashes. âChet must have built a fire after we left,â he called out to his brother.

Joe felt the ashes with the palm of his hand. âCold!â he declared. âThis fire has been out at least a couple of hours.â

âThat means it would still have been daylight.â

âBut the smoke! The Indians must have spotted it!â

There was a hollow feeling in the pits of their stomachs. The boys knew that there was only one explanation for Chetâs disappearance. He was in the hands of Vincenzol

CHAPTER XIV

A Threatening Message

âWE MUST rescue Chetâand fast!â Joe exclaimed. âNo telling what Vincenzo will do to him!â

âSimmer down. Letâs keep our heads,â Frank advised. âIf we end up getting captured ourselves, we wonât be able to help anybody.â

âOkay,â Joe said. âBut we canât stay here without food, water, and equipment. Iâd say our best chance is to start back to Montaraz as soon as itâs light. We might even meet Tico on the way.â

The boys cut some brush to improvise beds, and fell asleep. At dawn they began the long journey to the village. At one point they crossed a wide, parched stretch of desert plain. Their thirst became unbearable.

âI donât even see a cactus plant around,â Joe said weakly. âWeâve got to have water.â

âTry not to think about it,â Frank advised. âJust keep moving.â They plodded on.

A few minutes later the boys spotted an abandoned vehicle partially buried in the sand.

âIt must be a mirage,â Joe said.

âMirage nothing. Itâs a jeep.â Frank observed, and hastened to it.

âThis thingâs as hot as a griddle,â Joe remarked as he touched a portion of metal exposed to the sun.

âLooks as if the driver got bogged down in the sand and had to leave it,â Frank said. âThis thing mustâve been here for months.â

On the rear floor of the vehicle, Joe found several wrenches wrapped in a large plastic sheet.

âIf only we could squeeze water out of these,â he commented, trying to force a smile. He flung the plastic aside.

âHey! Wait a minute!â Frank commanded. âDonât throw that plastic sheet away. It might be the answer to our problem!â

Joe eyed his brother curiously. He retrieved the plastic sheet and handed it to him.

âYes! This might just do the trick,â Frank muttered as he examined it.

âAre you sure the heat hasnât gotten to you?â Joe asked.

âIâm fine,â his brother assured him. âI just remembered an article I read some time ago in a science magazine. It described a water generator which uses a plastic sheet just like this.â

Joeâs eyes widened. âSay! Now that you mention it, I remember you showing me the article. You start by digging a hole three or four feet across and about half that deep. Then you spread the plastic sheet over it and set a stone in the center. This causes the sheet to sink and form an inverted cone.â

âExactly,â Frank replied. âItâs based on the principle that even the driest soil contains some moisture. As the sun evaporates it, the water vapor condenses on the underside of the plastic sheet. The droplets then begin to trickle down to the point of the inverted cone and fall into a container.â

The boys grabbed a couple of wrenches and began scraping a hole in the soft earth. Frank removed a headlight from the jeep and broke off its stem to serve as a container. He placed it at the bottom of the hole.

âNow help me spread the sheet over it, Joe.â

When the job was finished, Joe picked up a stone and laid it in the center of the sheet, which sank down toward the container in the shape of a cone.

âNow all we have to do is wait,â Frank said.

âHow long will it take?â

âAccording to experiments, about a quart is produced every twelve hours. But we should have enough water to quench our thirst long before that.â

The Hardys sat beside the jeep. Removing their jackets, they spread them over their heads in order to ward off the hot rays of the sun. After several hours they checked on the progress of their water generator.

âIt worked like a charm,â Frank said, pointing to the clear water that had collected in the container.

Joe grinned. âThere must be at least a pint there.â

Frank took the first swig. âFinest water I ever tasted,â he quipped, and handed the container to his brother.

âYouâre right. Great stuff!â Joe glanced at the position of the sun. âItâll be dark within a couple of hours,â he continued. âLetâs try to cover a little distance by then. Weâll take the water generator with us.â

The boys got underway. Soon they found them selves moving into an area where they saw increasing signs of plant life.

âI see hawthorn bushes!â Joe exclaimed. âThey have those small red and yellow apples Tico told us about.â

The Hardys picked a supply of the fruit and ate heartily.

âItâs a far cry from Motherâs or Aunt Gertrudeâs home cooking,â Joe commented, âbut at least itâll keep us from starving.â

Exhausted, the boys fell asleep and did not awaken until dawn. As they continued their journey, Frank and Joe saw that they were moving into cactus country.

âWe wonât have to depend on our generator for water after all,â Joe observed. âThereâs enough in those cactus plants to fill a lake.â

As the Hardys were plodding over the top of a sandy knoll, Joe suddenly stopped and pointed. Frank looked down at the bottom of a shallow gully to see two Mexicans wearing sombreros. Nearby was a canvas lean-to for shelter, and over a fire was suspended a black kettle in which something was cooking.

âJust campers,â Joe muttered.

âMaybe,â Frank whispered. âBut weâd better not take any chances. They might be members of Vincenzoâs gang.â

Unaware of the Hardys, one of the men picked up a walkie-talkie and began speaking into it. Under cover of the brush, Frank and Joe crept closer to eavesdrop.

âMontaraz! Montaraz!â the Mexican exclaimed. âNo comprendo! Repita, por favor!-I do not understand! Please repeat!â There was a moment of silence. âBueno! Bueno!â he continued. âPavura aguardar!-Goodl Good! Pavura awaits!â

âDid you hear that?â Joe hissed. âHeâs talking to someone in Montaraz. And he mentioned Pavura!â

Frank did not reply. He signaled for Joe to withdraw a safer distance away, and they crept back across the knoll.

âWhat do you make of it?â Joe inquired. âWeâre still several miles from Montaraz. That walkie-talkie canât transmit so far.â

âMy guess is that Vincenzo has a string of men, spaced just within range of one another, extending from his headquarters to the village,â Frank replied.

âYou mean a chain of communication?â Joe asked.

âRight! Pretty clever, too. If Vincenzo used a single transmitter at his headquarters, it would have to be more powerful. That would increase the danger of his messages being picked up by the authorities. This way the signal range is very limited.â

âWhy donât we grab those two guys?â Joe snapped.

âNo,â Frank answered. âIt would cause a break in the chain and warn Vincenzo that something is wrong.â

âWell, at least weâve learned one fact. He must have a spy in the village.â

The boys resumed their journey, estimating that they would reach Montaraz by nightfall.

âWeâd better change our course slightly,â Frank advised, âso we donât stumble across any of Vincenzoâs men.â

âThey might be members of Vincenzoâs gang!â Frank whispered

Tired and dusty, the Hardys trudged into the outskirts of the village shortly after dark.

âThereâs only one person we can trust in Montaraz,â Frank said. âThatâs SeÃ±ora Santos. But we must be extra careful. Now that we know thereâs at least one spy in the village, we canât risk being seen.â

The boys crouched low and headed for Senora Santosâs home. At that hour the streets were deserted, but as the young detectives skirted the plaza, a man emerged from the cantina. The boys darted behind a tree until he walked by. When they reached the Santos house, Frank tapped lightly on the door.

âQuiÃ©n vive?âWho is there?â came the muffled voice of a woman from behind the door.

âThe Hardys,â Frank said.

âAh, los muchachos! One moment. I shall open the door,â announced Senora Santos.

âPut out your light first,â Frank replied. âWe donât want to be silhouetted in the doorway.â

The woman obeyed. Then she admitted the boys and relit the small oil lamp.

âDo you bring news of my husband?â she asked hopefully.

âIâm afraid not,â Joe said sympathetically.

âHas our friend Tico been here?â Frank inquired.

âNo, I not see him,â Senora Santos answered.

The Hardys glanced at each other worriedly.

âI do not think I see you again,â she muttered nervously.

âWhy not?â Frank questioned.

âThis morning I find a note under my door. It say I no speak with you if you come to our village. I not obey!â

âIs that all the message said?â Joe queried.

âNo,â the woman replied. Her face turned pale. âIt say that your two friends are in hands of Pavura. If you try to contact police, you never see them again, and I will not see my husband!â She burst into tears.

âGood night!â Frank exclaimed. âVincenzo has Tico as well as Chet!â

CHAPTER XV

Tunnel Escape

âNow weâre really in trouble!â Joe declared.

âItâs a cinch we canât go to the authorities,â Frank said nervously. âWeâd be risking the lives of Chet, Tico, and SeÃ±or Santos.â

The woman continued to sob and the Hardys tried to comfort her. âDonât worry,â Frank said. âWeâll figure out some way to rescue them.â

âIâm for going back to the cave,â Joe said.

âSo am I,â Frank agreed. âIt would be better if we had some help, but weâll have to do without it.â

âWhat about supplies?â Joe said.

SeÃ±ora Santos turned to the boys. âI give you food, and my husband has things to make camp. You may take what you need.â

She led the way to another room and pointed to a large wooden chest. Inside it, the boys found a pup tent, canteens, a small hatchet, and other useful items. Joe selected some rock-climbing tools, pitons and a coil of rope, and tucked them into his belt.

âMy uncle lives three miles north of the village,â Senora Santos said. âHe is elderly and cannot help you. But he has horses which you may borrow.â

âThank you, seÃ±ora,â Frank said with a bow.

The woman jotted a note in Spanish, which she handed to Joe, along with a golden locket. âGive my uncle this,â she instructed. âHe will know I have sent you.â

The Hardys decided to start immediately. They stalked out of the village and headed north. An hour later they found the hacienda of Senora Santosâs uncle without any difficulty. The old man took the note and locket, spoke rapidly to the boys in Spanish, and beckoned them to follow him to the corral. There he provided them with two chestnut-colored horses. The Hardys mounted and rode off, smiling and waving their thanks.

âThis is sure better than walking,â Joe declared.

âYou can say that again,â Frank replied. âBut weâd better not try traveling too far in the dark. Weâll put a little more distance between us and Montaraz, then stop to rest.â

After they had ridden an hour, the Hardys made camp and feasted from a supply of tortillas and dried fruit SeÃ±ora Santos had given them.

The next day the journey continued in a direction designed to avoid the men in Vincenzoâs chain of communication. The ride was dusty, hot, and fatiguing. The boys pushed on, however, at a rapid pace and reached their destination late that afternoon.

âWeâd better not get any closer to the cave than this,â Frank advised. âVincenzo is certain to have extra guards watching for intruders.â

âHereâs a good place to make camp,â Joe said as he examined a deep cleft in the rocks surrounded by heavy brush.

âGood,â Frank answered. âAnd thereâs enough vegetation around for the horses.â

Next day, before dawn, Frank and Joe started out on foot toward Vincenzoâs hideout. Cautiously they crept to the spot from where they could view the cave entrance in secret.

âTheyâve doubled the guard,â Joe observed.

âThat complicates matters,â Frank whispered. âBut first weâll have to find out where Chet and the others are being kept before we can plan a rescue.â

Just as the sun began to rise above the crest of the mountains, the Indian workers emerged from the cave.

âRight on schedule,â Joe remarked in a low voice.

âAnd some of the guards are going with them,â Frank said.

The workers were immediately followed by six Mexicans who were obviously captives. Two guards prodded them along with their rifles.

âThey must be the men who disappeared from the village!â Joe whispered excitedly.

âIâm sure of it,â his brother agreed. âOne of them must be Senor Santos.â

Suddenly something attracted Frankâs attention. âThatâs odd,â he muttered. âI hadnât noticed it before.â

âWhat?â

Frank pointed to a ledge farther up the slope above the cave. Two Indians had just appeared from behind a curtain made of twigs and brush.

âIt looks like the entrance to another cave,â Joe muttered in surprise.

âMaybe thatâs where Chet and Tico are being held prisoners,â Frank surmised. âIf we could reach that ledge, we could crawl along it without being seen.â

The boys decided to make an immediate attempt. They scanned the area and elected to work their way around the east side of the clearing, then up the craggy face of the slope.

âThere are plenty of rocks to give us cover,â Frank concluded.

The Hardys inched their way along. Progress was painfully slow when they reached the slope and began the grueling climb to the ledge. The boysâ pulses quickened as one of the guards in the clearing below looked up in their direction. But he turned away without spotting them.

Finally the Hardys reached their goal. They flattened themselves out on the ledge and pushed their way toward the place from which they had seen the Indians emerge. Frank carefully lifted up the lower corner of the curtain woven from twigs and brush.

âWhat do you see?â Joe whispered.

âItâs a cave all right,â Frank answered in a hushed voice.

âCarefull There might be more Indians inside.â

âI donât see any. Weâre in luck!â

The boys cautiously crawled in through the entrance. Then they got to their feet and examined their surroundings in the dim light. They were in a spacious chamber which narrowed toward the rear to form a corridor about the size of a subway tunnel. It appeared to lead deeper into the center of the mountain.

âThis must be another of Vincenzoâs storage rooms,â Joe remarked, noticing several rows of wooden crates.

Frank gazed curiously at a number of strange-looking, elongated objects stretched along one wall of the cave.

âThese seem to be rubber-coated nylon containers of some kind,â he said, examining them more closely.

âAnd theyâre about as long as that crazy rail car we took a ride on,â Joe added.

Suddenly the curtain covering the entrance moved aside. Two Indians walked into the cave. Unable to find a hiding place in time, the boys crouched low.

âCuando estarÃ¡ listo?âWhen will it be ready?â one of the Indians asked his companion.

The other was about to answer, when the two men came to an abrupt halt. They stared directly at the Hardys with startled expressions.

âAfter them before they warn the others!â Frank exclaimed.

The boys sprang up and hurled themselves toward the Indians. They crashed into the midriffs of the men and sent them tumbling to the ground. Frank lashed out with a right that knocked his opponent unconscious. The second Indian broke from Joeâs grasp. He darted to the cave entrance and shouted a warning to his companions. Joe rushed after him and dealt the Indian a blow that sent him sprawling.

âHow do we get out of here?â Joe cried as he and his brother heard the sound of shouting men drawing closer.

Frank peered at the long, dark corridor leading from the rear of the cave. âThat waylâ he ordered.

The boys stumbled through the inky blackness of the tunnel for a short distance. Then they pulled out their pencil flashlights and examined the path ahead.

âThis tunnel might lead to a dead end!â Joe declared.

âWe have no choice but to go onlâ Frank replied.

Already many Indians could be heard entering the tunnel in pursuit. In desperation, the Hardys broke into a frantic run. Finally they had to stop for a moment to catch their breath. As the boys did so, they gradually became aware of a new sound.

âDo you hear that?â Joe asked. They listened more intently.

âSounds like flowing water!â Frank replied.

Continuing on, they noticed that the sound became louder. At a point where the tunnel grew wider, the boys directed the beams of their flashlights a distance ahead.

Joe gasped. âLook! Itâs an underground river!â

They whirled to see the flickering glow of torches approaching from far down the tunnel.

âLetâs chance it and try swimming downstream!â Joe suggested frantically.

âOkay!â

The Hardys quickly removed their shoes, tied the laces together, and draped them around their necks. They jumped feet first into the water. No sooner had the icy current swept them away, when several Indians arrived on the scene.

âTheyâre not coming after us!â Joe sputtered.

The boys fought hard to keep their heads above the churning water as the river carried them through a dark tunnel. Minutes later, they saw a bright circle of light ahead.

âSunlight!â Frank shouted, but his joy suddenly froze to horror.

The underground river gushed through the opening and cascaded out of sight with a thunderous roar!

CHAPTER XVI

Face to Face

THE SWIFT current tumbled the Hardys toward the riverâs drop. They were about to be swept through, when Joe, in the lead, grabbed a segment of rock projecting from the wall of the tunnel about three feet above his head.

âHang on to me!â he shouted.

Frank clung to Joeâs waist and gazed through the opening. The water cascaded to jagged rocks below.

âDonât let go!â he screamed, âor weâre finished!â

âIâll hang on as long as I can!â Joe shouted.

The water pounded against the boys and threatened to carry them with it into the chasm.

âThe rock-climbing tools!â Frank cried out.

Joe hooked his left arm around the projection of rock and pulled a piton from his belt. Using the small hatchet in his right hand and holding the pin in the other, he hammered the piton into the tunnel wall. Then he took the coil of rope and threaded one end through the eyelet of the piton to form a double line.

Grasping it firmly with both hands, Joe let go of the rock and slowly fed out line. With the current pulling the boysâ bodies forward, they were swept outside the opening. They dangled precariously above the chasm as water gushed over them.

âThereâs a narrow ledge to our left!â Frank yelled. âIt looks just big enough for us to stand on if we can get close enough to reach it.â

He kicked out hard and the boys started to swing back and forth like a human pendulum. Frank, with only one hand around his brotherâs waist, reached out for the ledge with the other.

âAlmost!â he called as they arched up toward it.

Finally, after a hard swing, Frank managed to grab hold of the ledge. He and Joe pulled themselves up onto it. Then Joe released one half of the double line and pulled the rope free from the piton inside the tunnel.

âItâs about two hundred feet to the bottom of this waterfall,â Frank remarked. âAnd another two hundred to the top of the mountain,â he said as he peered at the sheer rock wall stretching above them.

âAnd itâs too far to the bottom for the amount of rope we have,â Joe observed. âOur best chance is to try making it to the top.â

Joe took one of his four remaining pitons and hammered it into the rock wall above the ledge. Using it as a foothold, he carefully lifted himself up. Then he drove another piton into the wall and repeated the procedure.

Frank began the dangerous climb immediately behind his brother. When Joe had used the last of his pitons, Frank reached down, loosened the lowermost one from the wall, and handed it to him. Each time the cycle was repeated, the boys edged a few feet closer to their goal.

Finally they reached the top and dragged themselves onto a level stretch of ground. âWhew!â Joe gasped. âI was beginning to think this hill was higher than Everest.â

The Hardys rested for a moment to regain their strength. Several minutes had passed when suddenly they were startled to see the shadows of two men fall across the ground from behind.

âOh, oh!â Frank muttered. âWe have company!â

Turning around, the youths saw two Indians standing just a few feet away.

âYou come!â one of them demanded. âPronto! Pronto!â He made a menacing gesture with his rifle.

âSome of Vincenzoâs men mustâve spotted us climbing the wall,â Frank said to his brother.

âAnd planned this little reception for us,â Joe added. âIt looks as if they mean business.â

The Indian repeated his order, then forced the boys to march in front of him. They slowly made their way down a steep, treacherous slope on the opposite side of the mountain. When they reached the bottom, the Indians took the captives back to their leaderâs hideout.

The Hardys were prodded into the cave and led directly to the chamber which served as a prisonersâ cell.

âChet and Tico are in there!â Joe exclaimed as one of the Indians unlocked the door of metal bars.

Frank and his brother were shoved inside and the door slammed behind them. Two Indians posted themselves outside as guards. Despite the boysâ predicament, they were overjoyed by the reunion.

âSorry I messed up your plans, fellows,â Chet said apologetically. âBut I didnât think a small campfire would raise much smoke.â

âItâs too late to think about it now,â Frank replied.

âWhat happened to you?â Joe asked Tico. âHow were you captured?â

âI had almost made it to Montaraz,â the Mexican youth explained, âwhen I came upon two men camped in the desert. They took me prisoner. One of them brought me back here after contacting Pavura on a small radio.â

âYou ran across a couple of men in Vincenzoâs communication chain,â Frank said. The Hardys then told the others about their own adventure.

âJuan, Marchetaâs son, is being held prisoner here,â Chet announced. âAnd also six men from the village of Montaraz.â

âAnd one of them is SeÃ±or Santos,â Tico added.

âThatâs what we figured,â Joe said. âWe saw them being taken from the cave.â

âDid they say anything about what Vincenzo and his workers are up to?â Frank queried.

âThey know only that they are made to work with the Indians on a small railroad,â Tico answered.

âWhy arenât you two forced to go along?â Joe asked curiously.

Tico grinned. âI overheard one of the guards say that Vincenzo thinks we are cleverer than the others,â he said. âHe does not feel it is worth the extra guards it would take to watch us.â

âIâd say Vincenzo is a good judge of character,â Chet muttered proudly.

Later, the Indian workers began to swarm into the cave. Then Juan Marcheta and the six prisoners from Montaraz were returned to the cell. Tico introduced them to the Hardys.

Juan, a lean, dark-haired boy, told the young detectives how he had been kidnapped by Vincenzo in order to stop his father from cooperating with the authorities.

âYour father is in hiding,â Frank told him. âIâm sorry I canât tell you where he is, but heâs safe.â

Santos, a tall, pleasant-looking man with a thick mustache, anxiously asked the Hardys if they had any news of his wife.

âWe saw her just two days ago,â Joe said. âSheâs well.â

âAh! That is goodlâ he replied with a sigh of relief.

âWhy did Vincenzo take you prisoner?â Frank asked him.

Santos said he had accidentally stumbled upon the gang leaderâs hideout while on a hunting trip. When he returned to Montaraz, he told some of his friends about his discovery.

âUpon leaving the cantina that night,â the Mexican continued, âI was struck on the head and knocked out. I was brought here.â He pointed to the other five men. âMy amigos came to look for me and were also captured.â

Joe remarked, âObviously Vincenzo wanted to keep you from telling anyone about his hideout.â

âAnd he put the strange symbol on the doors of your houses to terrorize the other villagers,â Frank surmised. âIt was meant to discourage them from getting curious.â

An Indian appeared and handed each of the prisoners a plate of dried maize. When they had finished eating, the weary captives fell asleep.

They were awakened the next morning by the sound of the Indian workers as they left the cave. Several guards came and escorted Santos and the other five men from the cell.

The Hardysâ thoughts turned to the possibility of escape. With Tico acting as their interpreter, they made an attempt to cajole their two guards into releasing them.

Joe creased his brow. âWeâre not going to get anywhere with those guys,â he said.

At that instant two men entered the cave and approached the boysâ cell. One of them was a tall, angular man with thinning black hair. His close-set eyes and sharp features gave his face an expression of evil. The Hardys recognized him as the Mexican they had encountered in Bayport.

âItâs Cardillo!â Joe declared.

âYou mean, Vincenzo!â his brother retorted.

The gangleaderâs companion, a short, wiry Mexican, stepped forward. âYou are in the presence of Pavura!â he exclaimed. âYou do not speak unless he bids you to do so!â

âDonât give us that Pavura stuff!â Joe snapped. âWe know his real name!â

Vincenzo glared at the boys. âYou think you are clever,â he snarled. âBut what you have learned will not do you any good.â

âI wouldnât count on that,â Frank retorted.

âI have no time for idle talk,â Vincenzo growled. He stepped closer to the cell door. âYou will tell me the whereabouts of Mr. Hardy and Senor Marchetalâ

âThey went fishing in Tampico,â Chet interrupted with a laugh.

âYou will advise your fat amigo to be quietlâ shouted Vincenzoâs companion.

âI order you to answer my questions!â the leader barked impatiently. âDoes your father know you are here in Baja?â

âYouâll have to figure that out for yourself!â Frank replied.

âYou force me to take stronger measures,â Vincenzo announced. âPerhaps the fiery brand of Pavura will loosen your tongues!â

The gangleader signaled the two guards, who immediately prepared a small pit of hot coals. Into it, one of the Indians thrust what appeared to be a branding iron. Minutes later he withdrew it from the pit. On the end of the iron, glowing white hot, was the mysterious symbol.

âNow!â Vincenzo cried. âWhich one of you would like to be the first to know the terror of Pavura?â

CHAPTER XVII

A Hot Melee

âYou wonât get away with this!â Joe shouted.

âOh, no?â Vincenzo snarled. âAnd since you are so quick to speak, I think you should have the honor of being first.â

Joe was led out of the cell and his hands were tied behind his back.

âHeâs not blufEng!â Chet cried in a quavering voice.

The gangleader signaled the Indian holding the branding iron, who then walked slowly toward Joe.

âStop!â Frank demanded angrily.

Suddenly, in a lightning move, Joe darted forward. Head low, he smashed into the midriff of the Indian, who jackknifed onto Joeâs shoulder. Then, snapping to an upright position, he flung the man to the floor.

âGrab the others!â Frank shouted to his companions.

The guards had neglected to relock the cell door. Flinging it open, the boys sprang into action. Frank caught the second guard squarely on the chin and knocked him unconscious, then he quickly untied his brotherâs hands.

A wild melee followed. Vincenzo lashed out and sent Tico sprawling to the ground.

âSocorro! Socorro!âHelp! Help!â screamed the gangleader as he started to flee from the cave.

Frank gave chase and downed Vincenzo with a flying tackle. They rolled across the ground, locked in a fierce struggle.

Chet, who had selected Vincenzoâs companion as his opponent, had pulled the Mexicanâs sombrero down over his eyes. The stocky man ran around the cave frantically trying to pull up the hat.

âI hear men shouting outside! Theyâre coming to help Vincenzo!â Tico exclaimed.

Several Indians appeared in the cave entrance. Joe grabbed one of the small barrels marked MUESTRA, and hurled it at them. The barrel smashed against the rocky wall above their heads and drenched the men with crude oil.

âNice going!â Chet yelled.

Joe picked up another barrel and threw it onto the pit of hot coals. It shattered, throwing up a huge orange ball of flame and thick smoke.

âAheee!â screamed an Indian in terror as he saw the fire.

Frank pulled Vincenzo to his feet and flung him into the path of two Indians about to attack. The men crashed to the ground in a tangled mass of arms and legs.

Meanwhile, Joe threw another barrel into the pit. The fire and smoke became more intense.

âSalga! Salga!âGet out! Get out!â Vincenzo shouted to his men.

Choking from the smoke, the Indians followed their leader out of the cave. Chetâs opponent finally managed to pull his sombrero free and raced out after the others.

The boys threw themselves down and placed their faces close to the ground where there was a shallow layer of clear air. When the fire and smoke subsided, they got to their feet.

âCome out! There is no escape!â they heard Vincenzo shout from outside the cave.

âIsnât there anything we can do?â Chet asked nervously.

âVincenzo and his men have us cornered,â Frank admitted. He glanced around. âAnd thereâs no way out of this place except by the entrance.â

âCome out at once!â the gangleader screamed. âOr I shall send my men in after youlâ

With no alternative but to obey, the boys walked out of the cave. As they emerged, the captives saw that Vincenzo was in a mad rage.

âYouâre too troublesome to be kept here! I shall have you all sent to a place from which you will never escape!â he growled. âYouâre going to take an undersea voyage!â

The boys were marched off with several guards prodding them along with rifles. Soon they were walking down a steep slope close to the narrow-gauge railroad the Indian workers had built. Frank and Joe noticed that the track now extended well beyond the point where they had stopped the speeding rail car.

âHm! Theyâve finished the project,â Joe commented.

âYes,â Frank agreed. âWe wondered where it went. I guess weâre about to find out.â

âYou no talklâ shouted one of the guards.

Finally they came to a cove on the east coast of the Baja Peninsula. The Hardys noticed that the track continued to the waterâs edge. Nearby a group of Indian workers was seated on the ground as if waiting for something.

The boysâ captors ordered them to sit down. Two guards were posted to watch them.

It was almost sunset when the Hardys and their friends were startled to see a submarine come to the surface out at sea. It slowly made its way into the cove.

âI can see the symbol on the conning tower,â Joe said in a hushed voice.

âIt must be the same sub we spotted in the cove in Sinaloa,â Frank added.

At that instant there came a rumbling sound. The boys looked to see several of the odd-looking rail cars come rolling down the track. Each of them carried a sausage-shaped object measuring about one hundred feet long.

âThey must be the rubber-coated nylon containers we found in the other cave!â Joe whispered to his brother.

Frank suddenly sat bolt upright. âSay! Do you remember the scrap of paper we found in Vincenzoâs hideout?â

âYes, I have it right here.â Joe pulled a fragment of paper from his pocket. They again looked at the printed words which read:

The practicability of draco ...

âThe word draco must be dracone!â Frank declared.

Joeâs eyes widened. âYouâre right! That must be it! I recall your showing me an article about dracones several months ago. Theyâre rubber-coated nylon containers designed to carry oil. A whole train of them can be towed behind a ship!â

âExcept in this case, theyâre being towed by a submarine!â

âSo thatâs what Vincenzo is up to. He must be smuggling oil out of the country,â Joe surmised. âBut where is he getting it from?â

Frank thought for a moment. âMy guess is that he got his hands on an oil well. Heâs keeping it a secret to prevent the Mexican government from taking over control.â

Chet was wide-eyed. âVincenzo wants it all for himself! So heâs selling oil to whoever will pay his price!â

The boys watched as the Indian workers began attaching triangular-shaped metal plates to the front and rear sections of the containers. The devices looked similar to the diving planes of a submarine.

âVery clever,â Frank whispered. âThose gadgets are used to keep the dracones under water when the sub is submerged.â

The Indians eased each of the containers into the water and linked them together by means of a special cable. The long train looked like a huge floating sea serpent.

The boys were now ordered to walk toward the submarine, which had tied up at the shore of the cove. Then they were forced to get aboard.

âLock âem in the aft cabin!â shouted a bearded crew member.

After climbing down through a hatch, the Hardys and their friends were led along a narrow passageway, then ordered into a small compartment. The door was slammed behind them and locked. A guard was posted outside.

âWhere could they be taking us?â Chet asked worriedly.

âWeâll soon learn if we donât figure out some way to escape!â Joe declared.

âLetâs think fast!â Frank urged.

Suddenly the boys felt a vibration and heard the rumbling sound of the craftâs diesel engines.

âIt is too late to do anything now!â Tico cried.

A feeling of panic gripped the four boys as the sub got underway. Where were they going? And what was in store for them when they arrived?

CHAPTER XVIII

Outwitting a Crew

THE BOYS searched frantically for an answer to their dilemma.

âWe must escape before the sub gets too far out to sea!â Frank declared.

Just then they heard the muffled voices of two men talking outside the cabin door.

âThe boss wants you to stay here on guard,â a man said. âI donât know why he picked you. Youâre always falling asleep.â

âWhatâs the difference?â the guard snapped. âThose kids are locked in. And even if they got out, where can they go aboard a sub?â

âKeep awake just the same,â the other man warned.

Then silence. The boys waited and listened. Less than an hour had passed when they detected the sound of snoring.

âHeâs asleep,â Joe whispered. âHereâs our chance.â

âBut the doorâs locked,â Chet said in a hushed voice. âWe canât break it downâevery crewman on this tub would hear us.â

Frank glanced around. âWe wonât have to,â he answered. âOur captors forgot one thing. The door hinges are on our side. All we have to do is force the pins out!â

Frank took a handkerchief from his pocket and wrapped it around the base of the hinge pin to reduce noise. Then he removed one shoe, and using the heel as a hammer, began to tap away lightly. Joe went to work on the second hinge.

The job was slow and demanded all the patience the Hardys could muster. Finally the pins were loose enough to be pulled free of the hinges.

Cautiously the boys eased the door aside. Outside they saw a grubby-looking man in a sailorâs cap and jacket propped up against a bulkhead. He was sound asleep.

The boys pounced on him at once, and before the surprised guard could utter a sound, he was gagged, then bound, and dragged into the cabin.

âSet the door back in place,â Frank whispered to Chet and Tico, âin case any of the crewmen come along.â

âWhatâs our next move?â Chet asked.

Frank rubbed his chin thoughtfully. âSomehow we must force the crew to turn around and go back to Baja.â

âMaybe we can disable the sub,â Joe suggested.

âLeaping lizards!â Chet exclaimed. âDonât do anything to sink us!â

âIf only we could put the electric motors out of commission,â Frank remarked.

Tico looked at the Hardys with a quizzical expression. âHow could we then return to Baja without power?â

âSubmarines have two sources of propulsion,â Joe explained. âDiesel engines are used when traveling on the surface, and battery-operated motors when under water.â

âIf we could sabotage the batteries somehow,â Frank said, âIâm sure the crew would turn back. They wouldnât risk going on without being able to submerge.â

Joe glanced down at their prisoner. âI have an idea!â he declared. âThe guard is about my size. Iâll put on his jacket and cap and try to work my way aft. None of the crew expects to see any of us outside the cabin. I might just get away with ruining the electric motors.â

âItâs worth a try!â Frank agreed. âBut weâve got to work fast. Somebody might check on the guard.â

Quickly donning the manâs jacket, Joe stepped out into the passageway. He pulled the cap low on his forehead and cautiously moved toward the rear of the submarine. There was not a single crewman in sight. As he edged his way along, the humming sound of the craftâs diesel engines gradually grew louder. Then the young detective spotted a compartment door directly ahead. It was partially open.

âThat must lead to the engine room,â he thought.

He crept closer to the door and peered through the crack. There he saw a single crewman checking gauges and making control adjustments.

Realizing he had to act instantly, Joe leaped in through the doorway. The startled crewman whirled and hurled a wrench at him. Joe ducked, then sprang toward his opponent. He caught the man with a sharp uppercut that sent him crashing to the floor and left him unconscious.

âNow, to put the motor batteries out of commission!â Joe thought.

He glanced about until he spotted a drum of lubricating oil. Joe shoved it close to the long row of batteries that operated the subâs electric motors. After quickly removing the caps which covered the battery cells, he pushed the drum over on top of them. Oil gushed into the batteries, and soon a thick, acrid smoke began to billow up.

At the same instant Frank, Chet, and Tico were confronted by a crewman who had been sent to check on the guard. But before he could warn his cohorts, the fellow was seized. In the brief struggle which followed, Frank kayoed him.

Joe sprang at his opponent

âLetâs get out of herelâ Frank whispered to Chet and Tico. âHead aftlâ

They raced down the narrow passageway. The three had not gone far when they saw Joe coming to meet them.

âGo the other way!â he warned. âThe engine room will be swarming with men in a minute!â

Already the smoke from the oil-soaked batteries was beginning to cause a commotion aboard the sub. The frantic shouts of crewmen could be heard echoing through the passageway.

âWe must find some place to hide!â Joe declared.

Frank pointed to a compartment door just ahead of them. âThatâs the forward torpedo room,â he said. âQuick! Inside!â

The boys dashed into the small room and eased the door shut behind them. Seconds later they heard crewmen scurrying through the passageway outside.

âThe captain wants everybody to report to the engine room!â a man shouted. âMake it snappy!â

Joe clutched his brotherâs arm. âDo you feel a change in the subâs motion?â he asked eagerly.

âYes!â Frank replied excitedly. âTheyâre turning around. We must be going back to Baja!â

âLeaping sailfish!â Chet blurted. âYour plan worked!â

Tico creased his brow. âThat is good,â he agreed. âBut we are still prisoners. How do we escape from here?â

At that instant the boys again heard shouts from the crewmen.

âThe kids broke out of the cabin!â one of them yelled. âTheyâre still aboard somewhere. Start searching every inch of this sub. Begin aft and work forward.â

The boys grew tense as the crewmen began their hunt through the various compartments. Gradually the men drew closer to the youthsâ hiding place.

âAfter you guys check the cabins, take a look in the forward torpedo room,â someone ordered.

âWeâre trapped!â Chet muttered nervously.

Joe glanced around. âWait a minute! There might be a way out of here!â

Frank immediately sensed what his brother had in mind. âYou donât mean the torpedo tubes?â

âWhy not?â Joe insisted. âBy now we canât be too far from shore. Iâll fire you fellows out through the tubes. I understand thereâs nothing to it.â

âBut it means leaving you behind,â Frank retorted. âNothing doing!â

âDonât worry about me,â Joe replied. âIâm sure I can get away.â

âHow?â

Their discussion was suddenly interrupted by sounds of the crewmen getting closer.

âNo time to explain now,â Joe said. âThis is our only chance. Hurry! Get into the tubes!â

Reluctantly Frank, Tico, and Chet selected one of the four torpedo tubes and climbed inside. Joe slammed the hatches shut behind them, grabbed the release lever, and fired. There was a loud whoosh of compressed air.

âWhat was that?â came the voice of a crewman from the passageway outside.

Joe flattened himself against the bulkhead adjacent to the compartment door. A split second later it was flung open and three crewmen rushed past the youth and into the torpedo room. Joe dashed out into the passageway unseen. He adjusted the cap and jacket and made his way amidships.

âTake it easy!â he mumbled to himself. âDonât look conspicuous!â

Joe located the control room, then climbed a narrow ladder leading up to the conning tower. Several crewmen saw him, but in the confusion, they obviously thought he was one of their group.

âThe kids have escaped!â came a voice from below.

All the deck hatches had been opened to help clear the air inside the sub. Joe climbed out, jumped from the conning tower onto the deck, and dived into the water. The craft glided on in the darkness, with the dracones slithering past like giant sausages.

Joe swam quickly toward the shore, which was silhouetted darkly against the night sky. It was not long before he sloshed out of the water onto the pebbly beach.

âI hope the others are all right,â he thought, peering along the shoreline.

Joe began walking in a direction away from the cove where he knew the sub was headed. His concern for his brother and friends increased. Then he heard a familiar bird call in the distance.

Joe cupped his hands over his mouth and returned the call. Shortly three figures loomed out of the darkness.

âIs that you, Joe?â came Frankâs voice.

âYes,â his brother responded. âAre you fellows okay?â

âJust fine!â Frank answered.

âSpeak for yourself, mastermind!â snapped Chet. âSo being shot out of a torpedo tube is easy, you said. Next time Iâll try it from a cannon.â

âChet just swallowed a bit too much water,â Frank remarked, laughing. âSo we rode on one of the dracones for a few minutes until he got his breath. Then we swam ashore.â

After Joe had told of his escape, Tico said, âThere are some awful mad men out there.â

âRight! Now we must plan our next move,â Joe said.

âIâd like to sneak back to the cove and see whatâs going on aboard the submarine,â Frank replied. âBut this time letâs not get caught. Some of Vincenzoâs Indians may still be around.â

The boys edged their way along the coast toward the cove. Gradually they began to detect the jumbled voices of many men talking from some distance away.

âItâs the subâs crew,â Joe whispered.

Frank peered through the darkness. âThe cove must be just beyond that low ridge of rocks ahead. If we climb to the top, we may be able to see whatâs going on.â

As the boys started up the side of the ridge, they suddenly heard a metallic, clicking sound behind them.

âPare!âStop!â a man ordered in a hushed, but determined voice.

The Hardys and their companions froze in their tracks!

CHAPTER XIX

The Trapper Trapped

Tico turned around, then looked straight ahead as the man uttered a rapid volley of words in Spanish.

âWho is he?â Frank demanded.

âI saw only the outlines of two men behind us,â Tico said. âOne of them has a rifle. He orders us not to turn around and to walk where he directs.â

The boys were forced to comply. But much to their surprise they were instructed to walk away from the cove.

âIf those guys are a couple of Vincenzoâs men,â Joe remarked, âweâre going the wrong way.â

âSilencio!â the man ordered.

The boys were marched toward a dense thicket slightly inland from the coast. On the other side was a small clearing. In the darkness the boys could make out the faint shapes of four horses. Nearby were three men dressed in military uniforms. One of them stepped forward.

âQuiÃ©n estÃ¡n ustedes?âWho are you?â he demanded.

Tico told him that his friends were Americans.

âAh, Americanos!â he said. âWhat are your names, please?â

When the Hardys identified themselves and Chet, the manâs eyes widened in surprise. âYou are the sons of SeÃ±or Fenton Hardy?â he asked.

The boys were startled by his question.

âWhyâerâyes, we are,â Frank stammered. âBut how did youâ?â

âI am Lieutenant JosÃ© Arandas of the Mexican Army,â the soldier announced, adding that he was leading one of several units sent to Baja on special assignment.

He explained that several reports had been received about a mysterious submarine in the area. The Army had been asked to cooperate with the Mexican Coast Guard in an investigation.

âWe were just about to make camp for the night,â Arandas continued, âwhen one of my men saw a submarine offshore. I sent out two scouts to watch it, and now they return with you muchachos.â

âBut how did you come to know our fatherâs name?â Joe asked.

âSeÃ±or Hardy recently arrived in Mazatlan to find that you were missing,â the lieutenant explained. âThe only information he was able to obtain was that you were last seen sailing off in a boat. But no one knew where you were going.â The soldier said that Mr. Hardy had notified the police, who in turn contacted the Army. All units were alerted to be on the lookout.

âWeâre sorry we caused Dad a lot of worry,â Frank sighed, âbut we didnât expect to be away for more than a couple of days. Weâd like to get word to him as soon as possible.â

âSÃ, sÃ,â Arandas said. âA helicopter will be in this vicinity tomorrow. We have a radio to talk with the pilot. He will relay a message to your father.â

âThanks,â Frank replied. âAnd now, Lieutenant, I believe we can help you.â The Hardys told the officer about their recent adventures in Baja.

âCaramba!â Arandas exclaimed. âAnd you say this hombre Vincenzo is smuggling oil out of Mexico?â

âWeâre certain of it,â Joe assured him.

The lieutenant barked an order to his men. He then turned to the boys. âI go to the cove to seize the submarine and its crew!â

âWait a minute!â Frank urged. âThat would only serve to warn Vincenzo. Heâd be sure to escape.â

âAnyway, the sub is out of commission for a while,â Joe added. âYou can grab it later.â

âThen you must lead me to Vincenzoâs hideout,â Arandas stated.

âWe will,â Frank agreed. âBut youâll need more men than you have now to capture him and his gang.â

The officer thought for a moment. âI shall contact our helicopter in the morning,â he said finally, âand have the pilot instruct all other scouting units in Baja to rendezvous with us. Perhaps Montaraz would be the place to meet. I have already sent two of my men there to question the villagers.â

Frank stiffened. âWhat?â he shouted. âYou sent two men to the village? This means trouble!â

âI do not understand,â Arandas said.

âWe believe Vincenzo has a spy in Montaraz,â Joe explained. âNews of soldiers arriving there will surely send Vincenzo running!â

âOur only hope is to find the spy!â Frank declared.

âHow?â Joe queried.

Frank quickly outlined a plan. They would rig up a directional antenna on Arandasâs walkie-talkie and use it to obtain a bearing on the spyâs radio signals if he should communicate with Vincenzoâs headquarters.

Early the following morning the loud, fluttering sound of a helicopter was heard approaching the coast. When it came within sight, Lieutenant Arandas picked up the walkie-talkie and contacted the pilot. He first requested that a message from the boys be relayed to Mr. Hardy in Mazat-Ian. Then he asked that the other scouting units rendezvous with him approximately one mile west of Montaraz.

When he had finished transmitting, Arandas handed the walkie-talkie to the Hardys. They quickly improvised a directional antenna from a length of wire and attached it to the radio.

âThat should do it,â Frank commented as he observed the rig. âNow weâd better start out for Montaraz.â

The soldiers mounted their horses. Each of the boys doubled with a rider and galloped off. Within a couple of hours the group arrived at the spot where Arandas was to meet with the other units.

âWeâll go the rest of the way on foot,â Frank informed the lieutenant. âIf we come up with anything, weâll let you know right away.â

âBuena suerte!âGood luck!â Arandas said.

Together with Chet and Tico, the Hardys rapidly walked the remaining mile to Montaraz. They did not enter the village, but posted themselves on the outskirts.

âSince we donât know what frequency the spy is transmitting on,â Frank remarked, âweâll have to keep sweeping through the entire band. Weâre close enough to the village to pick up a strong signal.â

The boys patiently and slowly worked the frequency knob of the walkie-talkie back and forth. An hour passed. Then suddenly a conversation between two men crackled from the speaker.

âCan you make out what theyâre saying, Tico?â Joe asked anxiously.

âYes!â the Mexican boy answered. âOne man says he has an urgent message for Vincenzo. He warns that there are soldiers in the village asking questions!â

Frank quickly turned the walkie-talkie until the axis of the circular directional antenna pointed toward the village. He then maneuvered the radio to the left and right until the signal faded completely. At that instant Joe recorded the direction of the bearing with his magnetic compass.

âHurry!â Frank ordered. âLetâs go to another spot and take a second bearing!â

The boys circled the village for some distance, then repeated the procedure. Now the voice of another man came from the speaker. âStay there and keep an ear open. Find out what theyâre up to and report to me.â Seconds later the transmissions ceased.

The Hardys drew a rough sketch of the village to scale. Then they plotted the two bearing lines.

âThey intersect at the extreme southeast corner of the village,â Joe said.

âAnd there are only two haciendas in that area,â Frank stated. âThat simplifies our search. The spy has to be at one or the other.â

Frank instructed Tico to hurry back to Arandas. âAsk him to meet us here with some of his men as soon as possible.â

It was already dark by the time Tico returned with the soldiers. The Hardys told the lieutenant about their discovery.

âWe must search the haciendas at once!â Arandas declared.

The boys and the three soldiers made their way toward the southeast corner of the village. As they edged toward their goal, they saw two rundown houses. They were in darkness and there was not a sound.

âNobody home,â Joe whispered.

âLetâs split up into two groups and search each of the homes,â Frank said.

Chet, Tico, and two of the soldiers crept toward one structure, while the Hardys and Arandas headed for the other. Frank carefully lifted the latch on the door and it eased open. He and the others stepped into an untidy room.

They pulled out their pencil flashlights and began a search. Arandas posted himself at the door.

After they had searched for several minutes, Joe sighed. âThereâs nothing here to give us a lead.â

Frank walked over to a large earthen jar resting in a corner of the room. Reaching inside, he let out a cry of surprise.

âWeâve come to the right place!â he exclaimed. âLook what I foundlâ He pulled out a walkie-talkie.

âTell the others to call off their search,â Frank told Joe. Soon Chet and the others arrived to inspect Frankâs discovery.

âI wonder where the spy is now,â Tico said.

âMaybe he flew the coop,â Chet suggested.

âPossibly,â Frank replied. âBut weâll wait for a while and hope he shows up.â

The watchers sat quietly in the darkened room. Less than an hour had passed when they heard the door latch being lifted. Then a short, stocky Mexican entered the room.

âGrab him!â Joe yelled.

The startled man cried out as two of the soldiers seized him. The boys directed the beams of their flashlights into the frightened manâs face.

Frank blurted out, âHeâs the guy who threatened us with a machete the first time we came to the village!â

Arandas was about to question him when the Mexican, slithering like a cornered snake, broke away from the soldiers. He leaped through an open window and headed for the center of the village, with the boys after him. Arandas pulled out his pistol but held his fire as the fugitive and his pursuers became blurred in the darkness.

The fleeing man raced across the plaza toward the cantina. In front of the building were two saddled horses. The fugitive leaped onto one and galloped off. Frank, who was closest to him, quickly mounted the second and started after him.

It was a bright moonlit night, so Frank had no difficulty keeping the escapee in sight. Gradually he closed the gap between them. As the chase continued, the young detective was startled to see about a dozen horsemen appear on the crest of a hill. Before Frank had a chance to wheel his mount around, he and his quarry were surrounded by the riders.

âThey look like some of Vincenzoâs men!â Frank thought. The man he had been chasing was obviously known to the riders. He whispered something to a lanky horseman, who then approached Frank.

âYou are one of zee Hardeez,â he said. âPavura weel want to see you! You come!â

He grabbed the reins of Frankâs horse and started off. The other riders trailed behind.

âWe are going to Vincenzoâs headquarters,â Frank mused. âThatâs the first place Joe will look for me. He can lead Arandas and his men right to it.â

But Frankâs hope was suddenly shattered when he noticed that they were going in a direction away from the hideout that he and his brother had discovered.

âVincenzo has relocated his headquarters!â he thought, trying not to panic.

Several of the riders behind him were dragging clumps of brush along the ground to erase the hoofprints. Not even Ticoâs tracking abilities could help him now!

CHAPTER XX

Helicopter Capture

FRANK ruled out making a break for it. The odds were too risky, since many of the men were armed. Others carried walkie-talkies.

âThese men must have made up the communication chain to Vincenzoâs old headquarters,â Frank thought.

With only a short rest in between, they rode all night. By morning their journey had taken them into a flat, dusty desert area. The sun was already intensely hot. Many of the men drank from canteens, but not one of them offered Frank a drop of water. By now he felt faint from thirst and hunger.

Presently the leader of the horsemen held up his hand. âStop!â he shouted. âOigalâListen!â

They heard a faint, fluttering sound. Gradually it became louder. The men turned and looked back apprehensively. A helicopter shot into view from over the crest of a hill.

âCaramba!â one of them screamed.

The craft circled the group several times, then made a low pass overhead. Many of the horses reared up and began to mill around, stirring up thick clouds of dust. The startled riders completely forgot about Frank and galloped off frantically in all directions.

âNice going!â the young detective yelled.

Shortly a second helicopter appeared. It hovered over the scene for a moment, then gently settled to the ground. Frank rode toward it as two of the occupants scrambled out of the cabin. His eyes widened in surprise when he recognized them.

âDad! Joe!â

âAre you okay?â his brother asked anxiously.

âIâm fine.â Frank nodded wearily. âBut, Dad! How did youâ?â

âI received the message you boys relayed to me in Mazatlan,â Mr. Hardy interrupted, âand Jack flew me to Baja right away. There the Mexican Army had a helicopter waiting to take me to Arandasâs camp.â

âDad arrived just in time to take part in our search for you,â Joe said. âWhen the other helicopter pilot spotted the horsemen he radioed us and we flew here to see what it was all about.â

The pilot of their craft, a young Mexican officer, called out to Mr. Hardy and the boys.

âI am in contact with the other helicopter,â he announced. âThe pilot says that some of the horsemen are heading toward what appears to be a large encampment in the hills east of here.â

âVincenzoâs new hideout!â Frank exclaimed.

âHe is flying back to report to Lieutenant Arandas,â the pilot continued. âHe says we should return also.â

Frank left his horse and the Hardys climbed aboard the craft. In less than fifteen minutes they arrived at Arandasâs camp, which was now crowded with soldiers.

Chet and Tico ran to meet the helicopter as it landed. They were elated to see that Frank was all right. Then the boys and Arandas discussed plans for the capture of Vincenzo and his gang.

âI shall have the helicopters fly my men to the encampment,â the lieutenant declared. âSeveral trips will be required, but we will save much time.â He ordered the airlift operation to begin at once.

âHow about letting us go with the first group?â Joe asked excitedly.

Arandas grinned. âI know you are very eager to capture this Vincenzo,â he said. âBut I am now responsible for your safety. First let me transport my men, then you shall follow.â

While the boys waited their turn, Mr. Hardy opened a large carton of fried chicken. âI had this prepared in Mazatlan,â he told them. âItâs the nearest thing to home cooking I could think of.â

âLet me at it!â Chet shouted jubilantly. The appetites of Frank and Joe, as well as Tico, equaled that of their hefty comrade. As they ate, Frank asked his father about Senor Marcheta.

âHeâs still in Mexico City,â Mr. Hardy replied. âAnd while I was with him, he told me what he knew about Vincenzo.â

The detective stated that Senor Marcheta had met Vincenzo in Spain several years before. The gangleader at that time was posing as a buyer for a Mexican textile firm.

âIt wasnât until the stock-fraud case came up,â Mr. Hardy explained, âthat Senor Marcheta discovered Vincenzo was actually a very clever confidence man. He has been involved in everything, from selling stolen goods on an international scale to peddling worthless stock in a diamond mine.â

Then the boys related their own adventures. Mr. Hardy was surprised to hear about the oil-smuggling operation.

âThatâs a new one even for Vincenzo,â he remarked. âHeâll have a lot to answer for.â

Finally Arandas announced that the Hardys and their companions could fly to the encampment. When they arrived, they saw that the soldiers had moved in on the gang. Indians were being lined up and questioned.

âWhereâs Vincenzo?â Frank asked quickly.

âHe fled before we could surround the encampment,â one of the soldiers replied. âWe have men searching the area for him now.â

Another soldier whispered something to Arandas. The lieutenant turned to the Hardys. âOne of your countrymen is among the captives,â he said.

âIt must be Elmer Tremmer!â Joe declared.

The boys and Mr. Hardy were led to a tent. Inside they found Tremmer in a state of panic.

âYouâve got to help me!â he pleaded. âI donât want to go to jail!â

âThen why did you run away?â Mr. Hardy asked.

Tremmer nervously mopped his brow. âI was frightened! Vincenzo said I would go to prison if I testified. Please, Mr. Hardy. Iâm not a member of Vincenzoâs gang! After all, it was I who sent you that note to beware of the mark on the door!â

âHow did you know what it meant?â the detective queried.

âTo be truthful, I wasnât sure,â Tremmer replied. He explained that before leaving Bayport, he had overhead one of Vincenzoâs men say an enemy had been dealt withâthat he had received the mark on the door!

âI feared for you and your sons,â Tremmer went on. âAnd again I sent a warning note to you at your hotel in Mazatlan.â

Interrogated about the oil deal, Tremmer said the gangleader had learned of an old Indian legend which described thick âblack waterâ of the mountain. Vincenzo guessed correctly that it was crude oil. While searching for the deposit, he had stumbled upon an isolated band of Indians. Being part Indian himself, Vincenzo quickly gained their confidence.

âEventually they showed him the source of the black water,â Tremmer continued. âIt was a rich pool of oil which oozed to the surface and did not have to be drilled.â

When Frank asked who was buying the oil, he was told that several Latin-American groups were bidding for it.

âThe price was low,â the prisoner said, âbut still Vincenzo was making a big profit.â

âQuite an operation,â Mr. Hardy remarked. âIt must have cost a lot of money to set up.â

âMost of it came from the Costa Quimico stock fraud,â the bookkeeper admitted.

Leaving Mr. Hardy to continue his detailed questioning, the four boys left the tent and were greeted by the villagers who had been kidnapped from Montaraz. With them was young Juan Marcheta. Amid voluble expressions of their gratitude, a rifle shot sounded, and soldiers ran toward the place where the helicopters had parked.

Suddenly rotor blades of one helicopter began to whirl. Seconds later it was airborne.

âCaramba!â screamed Arandas. âVincenzo is a clever scoundrel!â

âWhat happened?â Frank asked quickly.

âVincenzo was hiding nearby,â the lieutenant answered. âHe has just forced one of our pilots to fly him away!â

âWe can follow them in the other helicopter!â Joe suggested.

Arandas pointed at the fuel tank of the craft. âVincenzo thought of everything. He shot a hole in the tank. The fuel has already spilled away.â

âWhere could Vincenzo be headed?â Joe said.

âThat helicopter doesnât have enough range to take him very far,â Frank replied. âIâve a hunch heâs going to the cove to rendezvous with the submarine.â

âLetâs plug up the tank and go after him,â Joe urged.

Arandas creased his brow. âIt would not help to make such a repair. We do not have any more fuel available here.â

âThen we must do it the hard way,â Frank declared. âWeâll use horses.â

âBut itâll take us hours to reach the cove,â Joe argued.

âMaybe the sub crew hasnât finished repairing the damaged batteries,â Frank spoke up. âThe delay might be long enough for us to catch up with Vincenzo.â

The Hardys, Arandas, and twelve of his soldiers galloped off. It was already dark when they arrived on the coast a short distance south of the cove.

âHadnât we better go the rest of the way on foot?â Frank said in a hushed voice.

âYes,â Arandas replied.

They crept toward a low, rocky ridge, then scrambled up the slope to the top, with an excellent view of the cove.

âThe sub is still there,â Joe whispered.

âBut it looks as if the crew is busy getting ready to leave,â Frank observed as he watched men, carrying flashlights, scurry around the deck. Their voices could be heard plainly in the still, night air.

âWe must leave at once!â came Vincenzoâs voice.

âBut we havenât finished replacing the batteries,â shouted a crewman.

âYou can complete the work at sea,â the leader insisted. âIf we wait here until morning, the whole army will be on us!â

âThereâs not a moment to lose,â Frank urged. âWe must stop them.â

âI shall have my men spread out and converge on the submarine from all directions,â Arandas declared.

Cautiously they stalked toward the shore of the cove. Then, at Arandasâs signal, the soldiers charged ahead. The crewmen were caught completely off guard. Chaos followed.

âThereâs Vincenzo!â Frank yelled. âHeâs climbing out of the rear deck hatch! Donât let him get away!â

He and Joe rushed after the thief. Two crewmen who attempted to intercept the boys were bowled over by Joe, and all three splashed into the water.

Frank kept after Vincenzo, who leaped off the deck onto the shore. As the youth closed the gap between them, the man picked up a small boulder and hurled it at his pursuer.

Frank ducked, then lunged ahead and struck Vincenzo on the chin with a straight right. The man crumpled to the ground in a daze.

âThis is the end of the line for you!â Frank cried, yanking Vincenzo to his feet.

The action stopped as quickly as it had started. Arandas and his soldiers were lining up the crewmen on the shore of the c ove.

âWe found Arturo, the pilot of the helicopter, locked in a cabin aboard the submarine,â the lieutenant told the boys. âHe said he landed with Vincenzo just north of the ridge. I suggest you fly with your captive back to my camp near Montaraz when itâs light enough.â

The boys rested the remainder of the night. At dawn they took the handcuffed Vincenzo to the helicopter. The pilot started up the engine, engaged the rotor blades, and made a quick take-off. When they arrived at their destination, Arturo was dispatched to pick up Mr. Hardy and the others.

âHello, Dad!â the young detectives chorused as their father, Chet, and Tico were delivered back to the camp.

âI hear you boys did a great job,â Mr. Hardy said.

âWe were lucky,â Joe replied.

âDid you get any more information from Tremmer?â Frank inquired.

âYes,â Mr. Hardy said. âAnd heâs eager to return to Washington to testify. Weâll have to wait our turn with Vincenzo, though. The Mexican government gets first crack at him.â

âThereâs still one thing I canât figure out,â Joe said. âHow did Vincenzo get his hands on a couple of submarines?â

âTremmer told me about that too,â his father answered. âHe bought two obsolete subs in the States for scrap metal. Then he smuggled them out of the country for reconditioning. It wasnât difficult for him to dig up a few ex-submariners who werenât particular how they earned their money.â

âBy the way,â Chet said, âI wonder what happened to the other sub you spotted in Barmet Bay.â

âMy guess is that itâs headed here by way of Cape Horn,â Frank said. âThe trip will take several weeks.â

âWeâll notify the Mexican government to be on the lookout for it,â Mr. Hardy announced.

Leaving their prisoners with the soldiers, the Hardys, Chet, Tico, and Juan Marcheta were taken by helicopter to the small airport, where Jack Wayne was waiting.

âI just heard a flash youâll be interested in,â the pilot told them. âThe Argentine Navy boarded an unidentified submarine they spotted off their coast. The only markings it had was a strange symbol painted on the conning tower with the letter P on it. They seized the sub and its crew.â

âThat winds up the case,â Joe said with a wide grin. But he was looking forward to another challenging mystery to solve. In the near future, the young detectives would tackle The Hidden Harbor Mystery.

Soon the Hardy plane was winging back to Mazatlan with happy news for SeÃ±or Marcheta.

âIâm sure Father will want to celebrate with a feast,â Juan said.

âWeâre all for it,â Joe said, laughing. âBut donât have any bulls around. We donât want Chet getting more ideas about becoming a matador.â