The Secret of Skull Mountain

by Franklin W. Dixon

Frank stared at him in surprise. “Fix it!”

  Kleng turned his back abruptly and started for the rear of the store.

  Frank was annoyed. “Isn’t it a plumber’s job to help Bayport conserve water until the reservoir is ready?” he demanded.

  At this, the man turned and shot Frank an odd look. “Why don’t you try another plumbing shop? he suggested. “I work alone. Don’t have much time to go out on calls.”

  “What does he do, then?” thought Frank. He had a feeling there was something behind the fellow’s strange behavior. But he would have to find a plumber, and he wanted to return to Skull Mountain as quickly as possible.

  “Could you recommend another plumber?” he asked the man.

  “Sure.” Kleng went to a desk littered with account books and papers, and took an office letterhead from one of the drawers. Hastily he scribbled the name of a nearby shop and thrust the paper toward Frank.

  “Thanks,” said Frank, folding the paper and placing it in his pocket.

  Outside, the boy paused. “Something about Kleng rings false,” he thought. Slowly he took out the folded paper the plumber had given him.

  The fragments of two words seemed to leap out at him:LEN

  BAY

  Frank’s eyes widened. He unfolded the sheet. The top of the letterhead read: J. P. Kleng, Plumber. Centered below it was the word Bayport.

  The boy rapidly refolded the paper to its original creases. The same letters again stood out.

  Frank could not conceal his excitement. He was thinking of the two pieces of the telegram Fenton Hardy had found in Dr. Foster’s hotel room? Could the names Kleng and Bayport have been in that telegram? It was a clue worth tracing!

  As Frank was walking to his car, he noticed a tall, thin man stride past him. It was the fellow Frank and Joe had seen talking to Sailor Hawkins! Frank ducked into a nearby doorway.

  The man went into Kleng’s plumbing shop!

  CHAPTER VI

  Two Masked Men

  WHEN the man had gone inside, Frank walked past the window of the shop. He was just in time to see Kleng and the stranger disappear into the rear of the store.

  The youth debated whether to watch the shop and trail the tall stranger when he came out, or report the new developments to his father. He decided in favor of the latter. It seemed likely that Kleng was in some way involved with the disappearance of the scientist, and Fenton Hardy would want to know this as soon as possible. Frank jumped into the convertible and headed for home.

  Mr. Hardy was excited when he heard his son’s story. “If Kleng and the thin man are mixed up in Dr. Foster’s disappearance,” he pointed out, “they’ll meet again.” The investigator said he would like to know when, but the operatives who usually worked for him were on other assignments.

  “I have an idea,” said Frank. “Maybe I can help you.” He made a telephone call, but the line was busy. It was an hour later that he reached his friend Callie Shaw to ask if she and Chet’s sister Iola would help to scout Kleng’s shop.

  “I’ll be glad to, Frank,” she said. “But what should we look for?”

  Frank explained his suspicions of the plumber. “I thought maybe you and Iola could round up some of the girls and take turns going in the store on errands or window shopping nearby. Keep the place covered. If you see a tall, thin man go in, call my father at once.”

  Callie chuckled. “It sounds exciting. I’ll round up my female detectives right away!”

  “Be careful, Callie. Don’t let Kleng catch on!”

  “I’ll do the best I can!” the girl promised.

  Frank left for the camp, stopping to pick up Chet’s clothes on the way. Mrs. Morton insisted that he stay for dinner. Afterward, Chet’s father showed Frank some new milking machines. When Frank was finally able to excuse himself, it was growing dark.

  He headed the convertible toward Skull Mountain. After about fifteen minutes, he slowed down and turned off the concrete highway onto the dirt road which led to the mountain. He had gone only a short distance when, in the mirror, he saw the glare of a single headlight bearing down on him.

  Frank realized it was the headlight of a motorcycle. The boy slowed down, glancing at the speedometer. “I don’t get it!” he muttered. “A trooper doesn’t hand you a ticket for driving twenty on a country road!”

  The motorcycle drew abreast of the convertible. Frank gasped. There were two riders. They were not troopers! Both wore masks!

  “Pull over!” the driver ordered, and crowded the convertible to the side of the road. Frank turned off the ignition.

  The motorcycle halted alongside and the men got off. One was short with a thick, muscular body. Frank’s heart quickened. The other, who had been driving, was tall and thin!

  “Get out!” the thin man ordered.

  Warily Frank obeyed. He tried to distinguish the features of the two men, but their hatbrims were pulled low and their masks concealed their eyes, noses, and mouths.

  “What’s the idea?” Frank asked.

  “You’re Fenton Hardy’s kid,” the thin man stated. “What’s your father doing about the old man’s disappearance?” Frank looked at the speaker quizzically.

  “You know who we mean!” the thin man snapped. “What’s Hardy found out about him?”

  “I don’t know what you’re talking about!” Frank declared.

  The thin man shrugged. “There are ways to make you talk,” he said, turning to his companion. “Shall we give the kid a demonstration?”

  “Sure, Sweeper.”

  Frank desperately scanned the dirt road for an approaching car. But no light glimmered in the darkness.

  “Another thing,” Sweeper went on, “stop nosing into other people’s business on the mountain. There are plenty of graves up there—but there’s room for more.”

  “Forget the talk,” the shorter man said roughly. “Let me work on him.”

  As the man stepped toward him, Frank desperately decided to try an old trick. Suddenly he pretended to see someone behind the men. “Joe!” he yelled. “Over here!”

  Caught off guard, the two thugs half turned. Instantly Frank darted into the darkness, then dove behind a clump of bushes.

  Then he heard the men’s voices and realized they were searching the car!

  Footsteps approached, and Frank shrank back against the grass, feigning unconsciousness. Through almost closed eyes, he saw the two men staring down at him.

  The thin man kicked him hard in the ribs. Frank stifled a grunt and did not move.

  “He’s out like a light,” Sweeper exclaimed in disgust. “Must have hit his head. Come on! We can’t get any information out of him.”

  Frank waited until he heard the roar of their vehicle. It backfired, then disappeared into the night with its motor throbbing in a peculiar, uneven rhythm.

  Frank stood up shakily and returned to the convertible. The glove compartment was open and the front seat was littered with keys, flashlight bulbs, and crumpled papers and maps. Dazed, Frank drove slowly back to the highway to a farmhouse and asked permission to use the telephone.

  The farmer directed him to the telephone and he placed a call to his father. “What’s wrong, son?” Fenton Hardy queried when he heard Frank’s unsteady voice. “You sound as if you’re sick!”

  “Not sick, Dad. Just a little shaky. Don’t worry.”

  Frank told his father of the incident. Mr. Hardy was greatly interested in the possibility that one of the men was the tall, thin stranger Frank had seen on the mountain and later entering Kleng’s shop.

  “It looks to me,” the boy continued, “as if the mystery of the disappearing water is somehow tied up to your missing scientist!”

  “It certainly does, Frank,” the detective agreed. “And these fellows are dangerous.”

  After promising his father to be careful, Frank hung up and thanked the farmer for the use of his telephone.

  It was late when Frank arrived at the camp. Joe and Chet greeted him with enthusiasm, whic
h changed to concern when Frank told them all that had happened.

  “Zowie!” Chet exclaimed, shaking his head. “I’m not the only one who’s had troubles!”

  Frank grinned, and gave his friend the package of clothes. “Here, Chet,” he said. “Now you can join us when we go after the masked men!”

  “Not me!” Chet declared, cradling the package in his arms and walking toward his tent. “I’m too delicate for strong-arm stuff!”

  Frank noticed that the two engineers were not in camp. “Where are Bob and Dick?” he asked his brother.

  “They went down to the reservoir,” Joe replied. “This afternoon Bob painted a white stripe on a slab of rock, to mark the water line. They’ve gone to see how fast the level is falling.”

  As the boys walked toward their tents, Joe brought Frank up to date on his activities. That afternoon he had seen another column of smoke rising from the crest of the mountain. Joe had sighted the spot carefully, but when he had climbed the mountain, he had found no trace of a fire.

  “Same old story,” he concluded gloomily. “I found nothing!”

  Chet poked his head out of his pup tent. “Hey!” he called. “How about some chow? I’m starved!”

  The boys went into the shack. Chet whistled noisily while he made hot chocolate. With the rich drink they had sandwiches, and what remained of Aunt Gertrude’s cake.

  “I’m convinced that more important people than the squatters are interested in keeping Tarnack Reservoir from filling,” Frank declared as they ate. “I think we’ve got to look for something that ties in with Dr. Foster, the scientist Dad is searching for.”

  “I don’t see the connection,” Joe remarked as he watched Chet devour another sandwich.

  “I don’t either, Joe. Not yet,” said his brother. “But everything I found out today points to a tie-up between Kleng, Dr. Foster, and the thin man called Sweeper. And we saw that thin man on the mountain!”

  “It’s true.” Joe nodded. “By the way, Bob’s still convinced the water is running out through an underground channel.”

  “I don’t believe there is any old tunnel,” Chet grumbled.

  “How else can the water escape?” Frank asked.

  They thought in silence for a moment.

  “What I’d like to know is,” Joe said, “why does the channel drain off the water at night only?”

  “You’ve got me there,” Frank admitted. “But first we must prove that the underground channel exists and one way to do that is by planting floats in the reservoir and leaving them in at night!”

  “And if the tunnel exists, we can watch for the stuff at the other end!” Joe said excitedly.

  “But where is the other end?” Chet asked skeptically.

  “According to the book Bob read, the underground river empties into the bay at Bayport,” Frank replied.

  The boys were silent for a moment, each considering the possibilities of the plan.

  “Hey!” Chet said suddenly. “I smell smoke!”

  The boys sniffed. “See if something’s burning on the stove,” Frank suggested.

  Chet rose heavily from his chair and went to the stove. “Nothing here,” he reported. Then he stared. Wisps of smoke were curling through the floor boards of the wooden shack!

  “Fire!” he yelled, pointing to the floor.

  Frank and Joe leaped to their feet. “Come on, everybody out!” yelled Joe.

  “Take that bucket of water with you!” Frank ordered, pointing behind his brother.

  Joe grabbed up the bucket as Frank ran for the door. He pulled on the knob, but the door refused to open. Frank yanked again with all his strength.

  “Chet!” he gasped. “Give me a hand!” The heavy-set boy also gripped the doorknob, and together they strained at it.

  “It must be jammed,” Frank breathed. “It won’t budge!”

  “Try the windows!” Joe shouted.

  They ran to the two windows in the shack, then drew back. Flames were already licking the window sills!

  Joe emptied the water bucket on them, but the blaze continued to mount.

  “It’s no use!” cried Chet. “We’re trapped!”

  CHAPTER VII

  A Hatchet Job

  DESPERATELY the boys looked for a means of escape. Lifting a chair, Frank hammered at the wooden door. It would not yield. Smoke billowed thickly through the cracks in the floor, and a tongue of flame licked greedily at a plank.

  The smoke made the boys’ eyes water. They began to cough. Then, just when it seemed there was no way out, they heard excited voices. A moment later the blade of an ax bit through the door!

  “Bob-Dick!” Joe shouted. “Hurry!”

  “Boy, will I be glad to see them!” Chet spluttered weakly.

  “Grab anything you can carry!” Frank gasped.

  Quickly the boys gathered armloads of papers, camping equipment, and engineering instruments. Chet scooped up clothing.

  Blows from Bob’s ax had split the wood at the jamb. An instant later the door was flung back, and the boys ran into the open. They dropped their bundles and breathed deeply, filling their lungs with fresh mountain air.

  Meanwhile, shouts of “Fire!” came from the reservoir and the boys could see some of the sounding crew running up the slope with buckets of water.

  Bob and Dick were frantically shoveling sand from the nearby pile onto the flames. The Hardys and Chet pitched in, using whatever pots and pans they could lay hands on.

  When the last flame was out, the boys and men stood gasping for breath.

  “Frank,” said Bob wearily, “what happened?”

  “That’s what we’d like to know!” Joe declared.

  “A fire started under the shack,” Frank went on, “and when we tried to run out, we couldn’t get the door open.”

  “It was padlocked!” Dick said grimly.

  “Padlocked!” Joe gasped.

  “Yes,” Bob replied. “Someone snapped the lock shut while you were inside!”

  “And then set the fire!” Frank exclaimed.

  “Golly,” said Chet. “Who would do a thing like that?”

  “Someone who is desperate to get rid of us,” Dick replied bitterly.

  The sounding crew watched silently as the Hardys searched carefully around the smoking shack for a clue to the arsonist. They found none.

  Talking uneasily, the men started down the slope again. One of them said, “This party’s getting too rough for me.”

  “That’s all we need—” Bob remarked bitterly, “is for the crew to quit.”

  The boys and engineers examined the blackened shack and were relieved to see that the main damage was to the floor, windows, and door.

  “We can fix it,” Dick said. “We’ve got tools and lumber.”

  The Hardys helped Bob and Dick salvage whatever articles they could from the shack. Nearby, the engineers pitched two tents which Joe had rescued from the fire.

  Bob told the boys that he had gained some specific information from the white stripe with which he had previously marked the high-water level of the reservoir that afternoon.

  “When we got there tonight, the level of the water was one foot under the mark,” he said. “But the rock itself was damp for four feet above the stripe!”

  Dick summarized their findings. “During the afternoon the water rose four feet. And later five feet of it drained away!”

  “We’ve checked it daily and find that the story is always the same.”

  “Sounds as if the How is controlled in some way,” said Joe.

  Frank wanted to tell the engineers about his idea of planting articles in the reservoir at night, but he did not wish to arouse their hopes too soon. He caught Joe’s eye, and the younger Hardy understood that he was not to mention the plan.

  Early the next day, while the engineers repaired the shack, Frank and Joe went down to the reservoir and walked along the shore a few feet from the water. Chet trudged behind them.

  The slope at the water’s
edge was dotted with rocks, patches of shrubs, and creeping vines which extended under the water. Did one of the tangled masses conceal the mouth of the tunnel?

  The boys prodded the brush with long sticks, tearing away the thickly matted branches and leaves. The job was slow, difficult, and unrewarding.

  Now and then they looked up and saw men with earphones and sounding equipment working around the shore.

  When the sun was high overhead, one of the men gave a shrill whistle. He signaled the others and the crew climbed the hill, carrying their lunch boxes and gear into the shade of the trees above.

  “They’re going to have lunch, I bet,” said Chet. “How about us?”

  “Soon,” Frank said briefly. Both Hardys were intent on their job.

  After a while, Chet wiped his forehead. “Wow, is it hot!” The youth sat down heavily, then jumped up as if he had been shot. “Ow!” he yelled.

  He put his hand to the seat of his pants and gingerly pulled out a huge thorn. “That’s what I get for letting you two talk me into hunting for an old tunnel!” he said disgustedly.

  Joe turned to his brother. “What can you do with a guy like that?” he asked.

  Frank looked speculatively at the water. “We might duck him,” he suggested.

  “We might at that!” Joe’s eyes lighted up at the idea.

  Chet blanched. “Don’t you dare!” he pleaded.

  “Come on, Joe! Grab him!” yelled Frank. Laughingly the Hardys took hold of their friend. Frank clutched Chet’s struggling arms and shoulders while Joe held his feet.

  The stout boy shouted helplessly, “Oh, come on, fellows, let me down!”

  They started to swing the spluttering youth toward the water.

  “One!” Frank counted. “Two—”

  Suddenly a metallic sound rang out from the woods above them.

  “Hold it! Listen!” exclaimed Frank.

  Again and again the noise echoed from the mountainside over the silent sun-baked valley.

  “Come on!” Frank raced up the slope with Joe at his side and Chet slipping and sliding along behind.

  Panting, they reached the woods as the sound stopped. A moment later there was thrashing in the underbrush.