بخش 04

Ken rode the back seat of Joe’s motorcycle on the trip to High Street. He was warmly welcomed by Mrs. Hardy and Aunt Gertrude.

“I hope you enjoy your stay here,” said Mrs. Hardy, who knew that Frank and Joe had a good reason for inviting Ken. But neither woman asked questions in his presence.

“Your father probably will be out all day,” Mrs. Hardy told her sons. “He’ll phone later.”

While lunch was being prepared, Frank called police headquarters to give Chief Collig a report on what had happened at the deserted farmhouse.

“I’ll notify the FBI,” the chief said. “I’m sure they’ll want to send men out there to examine that truck and take fingerprints. Elekton,” the chief added, “had no record of any employee answering The Arrow’s description.”

“We’re working on a couple of theories,” Frank confided. “But nothing definite so far.”

After lunch the Hardys decided their next move was to try to find out more about the contents of the envelopes Ken had delivered to Peters.

“We could ask Elekton officials straight out,” Joe suggested.

His brother did not agree. “Without tangible evidence to back us up, we’d have to give too many reasons for wanting to know.”

Finally Frank hit on an idea. He telephoned Elekton, asked for the accounting department, and inquiredwhere the company had its printing done. The accounting clerk apparently thought he was a salesman, and gave him the information.

Frank hung up. “What did they say?” Joe asked impatiently.

“All Elekton’s printing is done on the premises!”

“That proves it!” Joe burst out. “The setup with Ken delivering envelopes to Peters isn’t a legitimate one, and has nothing to do with Elekton business.”

Meanwhile Ken, greatly mystified, had been listening intently. Now he spoke up. “Jeepers, Frank and Joe, have I been doing something wrong?”

In their excitement the Hardys had almost forgotten their guest. Frank turned to him apologetically. “Not you, Ken, We’re trying to figure out who has.”

Just then the Hardys heard the familiar chug of the Queen pulling up outside. The brothers went out to the porch with Ken. Chet leaped from his jalopy and bounded up to them. His chubby face was split with a wide grin.

“Get a load of this!” He showed them a badge with his picture on it. “I’ll have to wear it when I start work. Everybody has to wear one before he can get into the plant,” he added. “Even the president of Elekton!”

Suddenly Chet became aware of Ken Blake, “Hello!” the plump boy greeted him in surprise. Ken smiled, and the Hardys told their friend of the morning’s adventure.

“Boy!” Chet exclaimed. “Things are starting to pop! So you found that green truck!”

At these words a strange look crossed Frank’s face.

“Chet,” he said excitedly, “did you say everybody must show identification to enter Elekton’s grounds?”

“Yes-everybody,” Chet answered positively.

“What are you getting at, Frank?” his brother asked quickly.

“Before yesterday’s explosion, when we saw the gate guard admit the green truck, the driver didn’t stop-didn’t show any identification at all!”

“That’s true!” Joe exclaimed. “‘Mr. Markel doesn’t seem to be the careless type, though.”

“I know,” Frank went on. “If the green truck was sneaking in explosives-what better way than to let the driver zip right through.”

Joe stared at his brother. “You mean Markel deliberately let the truck go by? That he’s in league with the saboteurs, or the counterfeiters, or both?”

As the others listened in astonishment, Frank replied, “I have more than a hunch he is-and Docker, too. It would explain a lot.”

Joe nodded in growing comprehension. “It sure would!”

“How?” demanded Chet.Joe took up the line of deduction. “Markel himself told Ken the envelopes were for the printer. Why did Docker say Ken wasn’t at the mill the day I saw him? And what was the real reason for his being discharged?”

“I’m getting it,” Chet interjected. “Those men were trying to keep you from questioning Ken. Why?”

“Perhaps because of what Ken could tell us, if we happened to ask him about the envelopes he delivered,” Joe replied. Then he asked Ken if Markel and Docker knew that Joe had picked up the envelope the day of the near accident.

“I didn’t say anything about that,” Ken replied. The boy’s face wore a perplexed, worried look. “You mean Mr. Docker and Mr. Markel might be-crooks! They didn’t act that way.”

“I agree,” Frank said. “And we still have no proof. We’ll see if we can find some-one way or another.”

The Hardys reflected on the other mysterious happenings. “The green truck,” Frank said, “could belong to the gatehouse men, since it seems to be used for whatever their scheme is, and they are hiding it at the deserted farmhouse.”

“Also,” Joe put in, “if Victor Peters is the ‘old man,’ he’s probably an accomplice.”

“And,” Frank continued, “don’t forget that the bike Ken used was available to both Docker and Markel to deliver the warning note. The arrow shooting occurred near the mill; the attack on us in the woods that night was near the mill. The warning note found in Chet’s car was put there after Markel told him to go to the front gate. The guard probably lied to Chet the first day we went to the mill-he never did phone the personnel department.”

“Another thing,” Joe pointed out. “Both men are more free to come and go than someone working in the plant.”

There was silence while the Hardys concentrated on what their next move should be.

“No doubt about it,” Frank said finally. “Everything seems to point toward the mill as the place to find the answers.”

“And the only way to be sure,” Joe added, “is to go and find out ourselves. How about tonight?” Frank and Chet agreed, and the boys decided to wait until it was fairly dark. “I’ll call Tony and see if he can go with us,” Frank said. “We’ll need his help.”

Tony was eager to accompany the trio. “Sounds as if you’re hitting pay dirt in the mystery,” he remarked when Frank had brought him up to date.

“We hope so.”

Later, Joe outlined a plan whereby they might ascertain if Peters was an accomplice of Docker and Markel, and at the same time make it possible for them to get into the mill.

“Swell idea,” Frank said approvingly. “Better brush up on your voice-disguising technique!”

Joe grinned. “Ill practice.”

Just before supper Mr. Hardy phoned to say he would not be home until later that night.

“Making progress, Dad?” asked Frank, who had taken the call.”Could be, son,” the detective replied. “That’s why I’ll be delayed. Tell your mother and Gertrude not to worry.”

“Okay. And, Dad-Joe and I will be doing some sleuthing tonight to try out a few new ideas we have.”

“Fine. But watch your step!”

About eight-thirty that evening Chet and Tony pulled up to the Hardy home in the Queen.

Ken Blake went with the brothers to the door. “See you later, Ken,” Frank said, and Joe added, “I know you’d like to come along, but we don’t want you taking any unnecessary risks.”

The younger boy looked wistful. “I wish I could do something to help you fellows.”

“There is a way you can help,” Frank told him.

At that moment Mrs. Hardy and Aunt Gertrude came into the hall. Quickly Frank drew Ken aside and whispered something to him.

CHAPTER XVII

Secret Signal

WITH rising excitement, Frank, Joe, Chet, and Tony drove off through the dusk toward the old mill.

Chet came to a stop about one hundred yards from the beginning of the dirt road leading to the gatehouse. He and Tony jumped out. They waved to the Hardys, then disappeared into the woods.

Joe took the wheel of the jalopy. “Now, part two of our plan. I hope it works.”

The brothers quickly rode to the service station where they had been that morning. Joe parked and hurried to the outdoor telephone booth nearby. From his pocket he took a slip of paper on which Ken had jotted down the night telephone number of the Elekton gatehouse.

Joe dialed the number, then covered the mouthpiece with his handkerchief to muffle his voice. A familiar voice answered, “Gatehouse. Markel speaking.”

Joe said tersely, “Peters speaking. Something has gone wrong. Both of you meet me outside the Parker Building. Make it snappy!” Then he hung up.

When Joe returned to the Queen, Frank had turned it around and they were ready to go. They sped back toward the mill and in about ten minutes had the jalopy parked out of sight in the shadows of the trees where the dirt road joined the paved one.

The brothers, keeping out of sight among the trees, ran to join Chet and Tony who were waiting behind a large oak near the edge of the gatehouse grounds.

“It worked!” Tony reported excitedly. “About fifteen minutes ago the lights in the mill went out, and Markel and Docker left in a hurry.”“On foot?” Joe asked.

“Yes.”

“Good. If they have to take a bus or cab to town, it’ll give us more time,” Frank said.

Tony and Chet were given instructions about keeping watch outside while the Hardys inspected the mill.

The brothers explained where the Queen was parked, in case trouble should arise and their friends had to go for help.

Frank and Joe approached the mill cautiously. It was dark now, but they did not use flashlights. Though confident that the gatehouse was deserted, they did not wish to take any chances. As they neared the building the Hardys could see that the shutters were tightly closed. Over the sound of the wind in the trees came the rumble of the turning mill wheel.

The Hardys headed for the door. They had just mounted the steps when the rumbling sound of the wheel ceased.

In the silence both boys looked around, perplexed. ‘I thought it had been fixed,” Joe whispered.

“Seemed okay the other day.”

“Yes. But last time we were here at night the wheel stopped when we were about this distance away from it,” Frank observed.

Thoughtfully the boys stepped back from the mill entrance to a point where they could see the wheel.

They stood peering at it through the darkness. Suddenly, with a dull rumble, it started to turn again!

Mystified, the Hardys advanced toward the gatehouse and stopped at the entrance. In a short while the wheel stopped.

“Hm!” Joe murmured. “Just like one of those electric-eye doors.”

“Exactly!” Frank exclaimed, snapping his fingers. “I’ll bet the wheel’s not broken-it’s been rigged up as a warning signal to be used at night!

When someone approaches the mill, the path of the invisible beam is broken and the wheel stops. The lack of noise is enough for anyone inside to notice, and also, the lights would go out because the generator is powered by the wheel.”

The Hardys went on a quick search for the origin of the light beam. Frank was first to discover that it was camouflaged in the flour-barrel ivy planter. Beneath a thin covering of earth, and barely concealed, were the heavy batteries, wired in parallel, which produced the current necessary to operate the light source for the electric eye.

The stopping and starting of the wheel was further explained when Frank found, screened by a bushy shrub, a small post with a tiny glass mirror fastened on its side.

“That’s the complete secret of the signal!” he exclaimed. “This is one of the mirrors a photo-electric cell system would use. With several of these hidden mirrors, they’ve made a light-ring around the mill so an intruder from any side would break the beam. The barrel that contains the battery power also contains the eye that completes the circuit.”

“I’ll bet Markel and Docker rigged this up,” Joe said excitedly. “Which means there must be something in the mill they want very badly to keep secret! We must find a way inside!”The Hardys did not pull the wires off the battery connection, since they might have need of the warning system. Quietly and quickly the brothers made a circuit of the mill, trying doors and first-floor windows, in hopes of finding one unlocked. But none was.

“We can’t break in,” Joe muttered. Both boys were aware that time was precious- the men might return shortly. The young sleuths made another circle of the mill. This time they paused to stare at the huge wheel, which was turning once more.

“Look!” Joe whispered tensely, pointing to an open window-shaped space above the wheel.

“It’s our only chance to get inside,” Frank stated. “We’ll try climbing up.”

The Hardys realized it would not be easy to reach the opening. Had there been a walkway on top of the wheel, as there was in many mills, climbing it would have been relatively simple. The brothers came to a quick decision: to maneuver one of the paddles on the wheel until it was directly below the ledge of the open space, then stop the motion. During the short interval which took place between the stop and start of the wheel, they hoped to climb by way of the paddles to the top and gain entrance to the mill.

Joe ran back through the beam, breaking it, while Frank clambered over a pile of rocks across the water to the wheel. It rumbled to a stop, one paddle aligned with the open space above. By the time Joe returned, Frank had started to climb up, pulling himself from paddle to paddle by means of the metal side struts. Joe followed close behind.

The boys knew they were taking a chance in their ascent up the wet, slippery, mossy wheel. They were sure there must be a timing-delay switch somewhere in the electric-eye circuit. Could they beat it, or would they be tossed off into the dark rushing water?

“I believe I can get to the top paddle and reach the opening before the timer starts the wheel turning again. But can Joe?” Frank thought. “Hurry!” he cried out to his brother.

Doggedly the two continued upward. Suddenly Joe’s hand slipped on a slimy patch of moss. He almost lost his grip, but managed to cling desperately to the edge of the paddle above his head, both feet dangling in mid-air.

“Frank!” he hissed through clenched teeth.

His brother threw his weight to the right. Holding tight with his left hand to a strut, he reached down and grasped Joe’s wrist. With an aerialist’s grip, Joe locked his fingers on Frank’s wrist, and let go with his other hand.

Frank swung him out away from the wheel. As Joe swung himself back, he managed to regain his footing and get a firm hold on the paddle supports.

“Whew!” said Joe. “Thanks!”

The boys resumed the climb, spurred by the thought that the sluice gate would reopen any second and start the wheel revolving.

Frank finally reached the top paddle. Stretching his arms upward, he barely reached the sill of the opening. The old wood was rough and splintering, but felt strong enough to hold his weight.

“Here goes!” he thought, and sprang away from the paddle.

At the same moment, with a creaking rumble, the wheel started to move! CHAPTER XVIII The Hidden Room

WHILE Frank clung grimly to the sill, Joe, below him, knew he must act fast to avoid missing the chance to get off, and perhaps being crushed beneath the turning wheel. He leaped upward with all his might.

Joe’s fingers barely grasped the ledge, but he managed to hang onto the rough surface beside his brother.

Then together they pulled themselves up and over the sill through the open space.

In another moment they were standing inside the second floor of the building. Rickety boards creaked under their weight. Still not wishing to risk the use of flashlights, the Hardys peered around in the darkness.

“I think we’re in the original grinding room,” Frank whispered as he discerned the outlines of two huge stone cylinders in the middle of the room.

“You’re right,” said Joe. “There’s the old grain hopper.” He pointed to a chute leading down to the grinding stones.

Though many years had passed since the mill had been used to produce flour, the harsh, dry odor of grain still lingered in the air. In two of the corners were cots and a set of crude shelves for clothes.

Suddenly the boys hearts jumped. A loud clattering noise came from directly below. Then, through a wide crack in the floor, shone a yellow shaft of light!

“Someone else must be here!” Joe whispered.

The Hardys stood motionless, hardly daring to breathe, waiting for another sound. Who was in the suddenly lighted room?

The suspense was unbearable. Finally the brothers tiptoed over and peered through the wide crack.

Straightening up, Frank observed, “Can’t see anyone. We’d better go investigate.”

Fearful of stumbling in the inky darkness, the boys now turned on their flashlights, but shielded them with their hands. Cautiously they found their way to a door. It opened into a short passageway which led down a narrow flight of steps.

Soon Frank and Joe were in another small hall. Ahead was a partially opened door, with light streaming from it.

Every nerve taut, the young sleuths advanced. Frank edged up to the door and looked in.

“Well?” Joe hissed. To his utter astonishment Frank gave a low chuckle, and motioned him forward.

“For Pete’s sake!” Joe grinned.

Inside, perched on a chipped grindstone, was a huge, white cat. Its tail twitched indignantly. An overturned lamp lay on a table.The Hardys laughed in relief. “Our noisemaker and lamplighter!” Frank said as the boys entered the room. “The cat must have knocked over the lamp and clicked the switch.”

Although the room contained the gear mechanism and the shaft connected to the mill wheel, it was being used as a living area by the present tenants. There were two overstuffed chairs, a table, and a chest of drawers. On the floor, as if dropped in haste, lay a scattered newspaper.

“Let’s search the rest of the mill before Markel and Docker get back,” Joe suggested. “Nothing suspicious here.”

The Hardys started with the top story of the old building. There they found what was once the grain storage room. Now it was filled with odds and ends of discarded furniture.

“I’m sure nothing’s hidden here,” Frank said.

The other floors yielded no clues to what Docker and Markel’s secret might be.

Frank was inclined to be discouraged. “Maybe our big hunch is all wet,” he muttered.

Joe refused to give up. “Let’s investigate the cellar. Come on!”

The brothers went into the kitchen toward the basement stairway. Suddenly Joe gave a stifled yell.

Something had brushed across his trouser legs. Frank swung his light around. The beam caught two round golden eyes staring up at them.

“The white cat!” Joe said sheepishly.

Chuckling, the Hardys continued down into the damp, cool cellar. It was long and narrow, with only two small windows.

Three walls were of natural stone and mortar. The fourth wall was lined with wooden shelves. Frank and Joe played their flashlights into every corner.

“Hm.” There was a note of disappointment in Joe’s voice. “Wheelbarrow, shovels, picks-just ordinary equipment.”

Frank nodded. “Seems to be all, but where are the old bricks and lumber that Ken said were stored here?”

“I’m sure the stuff was never intended for Elekton,” Joe declared. “More likely the mill. But where? In a floor? We haven’t seen any signs.”

Thoughtfully the boys walked over to inspect the shelves, which held an assortment of implements. Frank reached out to pick up a hammer.

To his amazement, he could not lift it. A further quick examination revealed that all the tools were glued to the shelves.

“Joel” he exclaimed. “There’s a special reason for this-and I think it’s camouflage!”

“You mean these shelves are movable, and the tools are fastened so they won’t fall off?”

“Yes. Also, I have a feeling this whole section is made of the old lumber from Pritos’ yard.”

“And the bricks?” Joe asked, puzzled.His brother’s answer was terse. “Remember, this mill was used by settlers. In those days many places had hidden rooms in case of Indian attacks-“

“I get you!” Joe broke in. “Those bricks are in a secret room! The best place to build one in this mill would have been the cellar.”

“Right,” agreed Frank. “And the only thing unusual here is this shelf setup. I’ll bet it’s actually the entrance to the secret room.”

“All we have to do is find the opening mechanism,” Joe declared.

Using their flashlights, the boys went over every inch of the shelves. These were nailed to a backing of boards. The Hardys pulled and pushed, but nothing happened. Finally, on the bottom shelf near the wall, Frank discovered a knot in the wood. In desperation, he pressed his thumb hard against the knot.

There was the hum of a motor, and, as smoothly as though it were moving on greased rails, the middle section of shelves swung inward.

“The door to the secret room!” Frank exulted.

Quickly the boys slipped inside the room and shone their flashlights around. The first thing they noticed was the flooring-recently laid bricks. Frank snapped on a light switch beside the entrance.

The boys blinked in the sudden glare of two high-watt bulbs suspended from the low ceiling. The next instant both spotted a small, handprinting press.

“The counterfeiters’ workshop!” they cried out

On a wooden table at the rear of the room were a camera, etching tools, zinc plates, and a large pan with little compartments containing various colors of ink. At the edge of the table was a portable typewriter.

Frank picked up a piece of paper, rolled it into the machine, and typed a few lines. Pulling it out, he showed the paper to Joe.

“The machine used to type the warning note Dad got!” Joe exclaimed excitedly. “The counterfeiters must have thought he was on their trail.”

“And look here!” exclaimed Frank, his voice tense. A small pile of twenty-dollar bills lay among the equipment. “They’re fakes,” he added, scrutinizing the bills. “They’re the same as Chet’s and Tony’s.”

Joe made another startling discovery. In one corner stood a bow, with the string loosened and carefully wound around the handgrip. A quiver of three hunting arrows leaned against the wall nearby.

Excitedly Joe pulled one out. “The same type that was fired at the girls,” he observed. “This must belong to The Arrow!”

“Docker matches his description,” Frank pointed out. “He easily could have colored his hair gray.”

The Hardys were thrilled at the irrefutable evidence all around them, “Now we know why Markel and Docker rigged the mill wheel-to give a warning signal when they’re working in this room!”

“Also, we have a good idea what was being sent to Peters in the envelopes-phony twenty-dollar bills!”

“Let’s get Dad and Chief Collig here!” Joe urged, stuffing several of the counterfeits into a pocket.As the boys turned to leave, the lights in the secret room went out. Frank and Joe froze. They realized the mill wheel had stopped turning.

“The signal!” Joe said grimly. “Someone is coming!”

CHAPTER XIX

Underground Chase

THE HARDYS knew this was the signal for them to get out of the secret room-and fasti As they hurried into the cellar, the lights came on again. With hearts beating faster, they started for the stairway. But before the boys reached it, they heard the mill door being unlocked, then heavy footsteps pounded overhead.

“Docker!” a man’s voice called. “Markel! Where are you!”

The Hardys listened tensely, hoping for a chance to escape unseen. When they heard the man cross the ground floor and go upstairs, Joe whispered, “Let’s make a break for it!”

The boys dashed to the steps. They could see a crack of light beneath the closed door to the kitchen.

Suddenly the light vanished, and the rumble of the mill wheel ceased.

The Hardys stopped in their tracks. “Somebody else is coming!” Frank muttered. “Probably Docker and Markel. We’re trapped!”

Again the brothers heard the mill door open. Two men were talking loudly and angrily. Then came the sound of footsteps clattering down the stairs to the first floor.

“Peters!” The boys recognized Docker’s voice. “Where in blazes were you?”

Frank and Joe nudged each other. Victor Peters was in league with the gatehouse men!

“What do you mean? I told you I’d meet you here at eleven,” snarled Peters.

“You must be nuts!” retorted Markel. “You called here an hour ago and said there was trouble and to meet you at the Parker Building.”

Peters’ tone grew menacing. “Something’s fishy. I didn’t phone. You know I’d use the two-way radio.

What’s the matter with you guys, anyway?”

“Listen!” Markel snapped. “Somebody called here and said he was you. The voice did sound sort of fuzzy, but I didn’t have a chance to ask questions-he hung up on me. I thought maybe your radio had conked out.”

The Hardys, crouched on the cellar stairs, could feel the increasing tension in the room above. Docker growled, “Something funny is going on. Whoever phoned must be on to us, or suspect enough to want to get in here and snoop around.”

“The Feds! We’ll have to scram!” said Markel, with more than a trace of fear in his voice. “Come on!

Let’s get moving!”“Not so fast, Markel!” Docker barked. “We’re not ditching the stuff we’ve made. We’ll have a look around first-starting with the cellar.”

The men strode into the kitchen. Below, Frank grabbed Joe. “No choice now. Into the secret room!”

Quickly the brothers ran back into the workshop. Frank pulled the door behind him and slid the heavy bolt into place.

Tensely the brothers pressed against the door as the three men came downstairs into the basement.

Frank and Joe could hear them moving around, searching for signs of an intruder.

“I’d better check the rest of the mill,” Docker said brusquely. “You two get the plates and the greenbacks. Go out through the tunnel, and I’ll meet you at the other end. Well wait there for Blum to pay us off, then vamoose.”

“We’re in a fix, all right,” Joe said under his breath. “What tunnel are they talking about?”

“And who’s Blum?” Frank wondered.

The boys heard the hum of the motor that opened the secret door. But the bolt held it shut.

“The mechanism won’t work!” Markel rasped.

“Maybe it’s just stuck,” said Peters.

The men began pounding on the wood.

“What’s going on?” Docker demanded as he returned.

“We can’t budge this tricky door you dreamed up,” Peters complained.

“There’s nothing wrong with the door, you blockheads!” Docker shouted. “Somebody’s in the room!

Break down the door!”

In half a minute his order was followed by several sharp blows.

“Oh, great!” Joe groaned. “They’re using axes!”

“We won’t have long to figure a way out,” Frank said wryly.

“Way out!” Joe scoffed. “There isn’t any!” Frank’s mind raced. “Hey! They said something about leaving through a tunnel! It must be in here.”

Frantically the Hardys searched for another exit from the secret room. They crawled on the floor, and pried up one brick after another looking for a ring that might open a trap door. “Nothing!” Joe said desperately. All the while the men in the cellar kept battering away at the door. “Good thing that old lumber is such hard wood,” Frank thought. “But they’ll break through any minute.” “Look!” Joe pointed.

“Under the bench!” Frank noticed a shovel lying beneath the work-table. The boys pushed it aside, and saw that the wall behind the table was partially covered with loose dirt. On a hunch Frank grabbed the shovel and dug into the dirt.

“This dirt might have been put here to hide the entrance to the tunnel!” he gasped.

“It better be!” His brother clawed frantically at the dirt.At the same moment there was a loud splintering noise. The Hardys looked around. A large crack had appeared in the bolted door.

One of the men outside yelled, “A couple more blows and we’ll be in.”

Frank dug furiously. Suddenly his shovel opened up a small hole in the crumbly dirt. Joe scooped away with his hands. Finally there was a space big enough for the boys to squeeze through. Without hesitation, Frank wriggled in, then Joe.

From behind them came a tremendous crash and the sound of ripping wood. Markel’s voice shouted, “Into the tunnel! After ‘em!”

The Hardys heard no more as they pushed ahead on hands and knees into the damp darkness of an earthen passageway.

Joe was about to call out to his brother when he became aware that someone was crawling behind him.

“No room here for a knockdown fight,” he thought, wondering if the pursuer were armed.

The young detective scrambled on as fast as he could in the narrow, twisting tunnel. He managed to catch up to Frank, and with a push warned him to go at top speed.

“Somebody’s after us!” Joe hissed. “If only we can outdistance him!”

The underground route was a tortuous, harrowing one. The Hardys frequently scraped knees and shoulders against sharp stones in the tunnel floor and walls. They had held onto their flashlights, but did not dare turn them on.

“This passageway is endless!” Frank thought. The close, clammy atmosphere made it increasingly difficult for him and his brother to breathe.

Joe thought uneasily, “What if we hit a blind alley and are stuck in here?”

The boys longed to stop and catch their breath, but they could hear the sounds of pursuit growing nearer, and forced themselves onward faster than ever.

Frank wondered if Chet and Tony had seen the men enter the mill and had gone for help.

“We’ll need it,” he thought grimly.

Suddenly the brothers came to another turn and the ground began to slope sharply upward.

“Maybe we’re getting close to the end,” Frank conjectured hopefully.

Spurred by possible freedom, he put on a burst of speed. Joe did the same. A moment later Frank stopped unexpectedly and Joe bumped into him.

“What’s the matter?” he barely whispered.

“Dead end,” reported his brother.

Squeezing up beside Frank, Joe reached out and touched a pile of stones blocking their path. The boys now could hear the heavy breathing of their pursuer.

“Let’s move these stones,” Frank urged.Both Hardys worked with desperate haste to pull the barrier down. They heaved thankful sighs when a draft of fresh air struck their faces.

“The exit!” Joe whispered in relief.

The brothers wriggled through the opening they had made and found themselves in a rock-walled space.

“It’s the cave by the river, Joe!” Frank cried out. “Someone put back the rocks we removed!”

The boys clicked on their flashlights and started toward the entrance of the cave.

“We beat ‘em to it!” Joe exclaimed.

“That’s what you think!” came a harsh voice from the entrance.

The glare from two flashlights almost blinded the Hardys. Docker and Markel, with drawn revolvers, had stepped into the cave.

CHAPTER XX

Solid Evidence

FOR a second the two armed men stared in disbelief at Frank and Joe. “The Hardy boys!” Docker snarled. “So you’re the snoopers we’ve trapped!”

There was a scuffling in the tunnel behind the boys. A stocky man, huffing and puffing, emerged from the tunnel. The Hardys recognized him instantly: the counterfeit passer, Victor Peters.

The newcomer gaped at the Hardys. “What are they doing here?”

“A good question!” Markel snapped at his accomplice. “You told us on the two-way radio you’d locked ‘em up with the truck.”

Peters whined, “I did. They must’ve broken out.”

“Obviously.” Docker gave him a withering look.

Frank and Joe realized that Peters had not returned to the old farmhouse.

Docker whirled on them. “How did you escape?”

The boys looked at him coldly. “That’s for you to find out,” Joe retorted.

“It’s a good thing Markel and I decided to head ‘em off at the cave,” Docker added angrily. “Otherwise, they would have escaped again.”

The Hardys could see that the men were nervous and edgy. “I’m not the only one who made a mistake,”

Peters growled. “I told you a couple of days ago to get rid of that kid Ken when these pests started asking about him, and then found the tunnel. We could have thrown ‘em off the scent!”

While the men argued, the Hardys kept on the alert for a chance to break away. Markel’s eye caught themovement, and he leveled his revolver. “Don’t be smart!” he ordered. “You’re covered.”

Peters continued the tirade against his confederates. “Docker, you should’ve finished these Hardys off when you put ‘em in the boat that night! And you”-Peters turned on Markel- “you could have planted a dynamite charge in their boat instead of just monkeying with the throttle.”

The Hardys, meanwhile, were thankful for the precious minutes gained by the men’s dissension.

“Tony and Chet might come back in time with help,” Joe thought.

Simultaneously, Frank hoped that Ken Blake had carried out his whispered instructions.

Docker glanced nervously at his watch. “Blum ought to be here,” he fumed.

“Who’s Blum?” Frank asked suddenly. “One of your counterfeiting pals?”

Docker, Markel, and Peters laughed scornfully. “No,” said Markel. “We’re the only ones in our exclusive society. Paul Blum doesn’t know anything about our-er-mill operation, but it was through him we got the jobs at the gatehouse. The whole deal really paid off double.”

Docker interrupted him with a warning. “Don’t blab so much!”

Markel sneered. “Why not? What I say won’t do these smart alecks any good.”

Joe looked at the guard calmly. “Who paid you to let the green panel truck into Elekton?”

All three men started visibly. “How’d you know that?” Markel demanded.

“Just had a hunch,” Joe replied.

The former guard regained his composure. “We’ll get our money for that little job tonight.”

Frank and Joe felt elated. Paul Blum, whom these men expected, must be the sabotage ringleader! “So that’s what Markel meant by the deal paying off double,” Frank thought. “He and Docker working the counterfeit racket on their own-and being in cahoots with the saboteurs.”

Frank addressed Markel in an icy tone. “You call blowing up a building a ‘little job’?”

The counterfeiters’ reactions astonished the Hardys. “What!” bellowed Markel, as Docker and Peters went ashen.

Joe snorted. “You expect us to believe you didn’t know explosives were in that truck?”

Victor Peters was beside himself with rage. “Fools!” he shrilled at Docker and Markel. “You let yourselves be used by saboteurs? This whole state will be crawling with police and federal agents.”

The gatehouse men, though shaken, kept their revolvers trained on the Hardys. “Never mind,” Docker muttered. “Soon as Blum shows up we’ll get out of here and lie low for a while.”

Frank and Joe learned also that Docker and Markel actually were brothers, but the two refused to give their real names.

“You, Docker, are known as The Arrow, aren’t you?” Frank accused him.

“Yeah. Next time I’ll use you boys for targets!” the man retorted threateningly.The Hardys kept egging the men on to further admissions. Docker and Markel had been approached several months before by Blum who tipped them off to good-paying jobs at the Elekton gatehouse.

Docker had cleverly forged references and identification for Markel and himself.

As soon as he and Markel had obtained the jobs, Blum had instructed them to buy the truck secondhand in another state, and told them only that Markel was to lend Blum the truck on a certain day when notified, let him through the gate, then out again soon after closing time. The guard would be handsomely paid to do this.

When Markel and Docker had become settled in the mill, the two had discovered the secret room and tunnel, which once had been a settlers’ escape route. The men had wasted no time in setting it up for their counterfeiting racket, and often used the nondescript green truck to sneak in the required equipment.

“Who rigged up the electric-eye signal?” Frank queried.

“My work,” Docker replied proudly.

As the boys had surmised, Peters, an old acquaintance of theirs, was “the old man” at the deserted farmhouse. When the boys had left the mill that morning Docker had radioed Peters, telling him if the Hardys showed up at the farm, he was to trap them.

“No doubt you planned to finish us off when you came back,” Joe said.

Peters nodded.

Frank said to Docker, “I must admit, those twenties are pretty good forgeries. The police think so, too.”

The counterfeiter smiled in contempt. “Your fat friend sure was fooled.”

He explained that his skill at engraving, which he had learned years ago, had enabled him to make the plates from which the bills were printed.

“Which one of you rode Ken’s bike and left the typed warning for our father?” Frank asked.

“I did,” Markel replied promptly.

“Why? He wasn’t involved with the counterfeiting case.”

We thought he was when we overheard a company bigwig say Fenton Hardy was ‘taking the case.’”

“Yeah,” Docker said. “I wasn’t kidding when I sent the warnings-on paper and by phone.”

He had acquired some sheets of bond paper from Elekton on a pretext; also the Manila envelopes used to deliver the bogus money to Peters. Docker admitted he had “unloaded” the counterfeit twenty at Pritos’ yard by mistake.

Peters broke in abruptly. “We’d better get rid of these kids right now!”

The three men held a whispered conference, but Docker and Markel did not take their eyes from the Hardys. Suddenly the boys’ keen ears detected the put-put of an approaching motor-boat.

One thought flashed across their minds-Chet and Tony were bringing help. But in a few minutes their hopes were dashed! A heavy-set, dark-haired man peered into the mouth of the cave.

“Blum!” Market said.”Who are these kids?” Blum asked, squinting at Frank and Joe.

“Their name is Hardy-“ Docker began, but Blum cut him short.

“Hardy!” he said sharply. “Listen-I just gave Fenton Hardy the slip at the Bayport dock. He was on a police launch.”

“We’ve got to move fast!” Markel urged. “Docker and I caught these sons of his snooping. Pay us what you promised and we’ll scram.”

Blum looked disgusted. “Stupid amateurs! You let kids make it so hot you have to get out of town?” The heavy-set man pulled out his wallet. “Here’s your cut for letting me into the plant,” he continued scornfully.

“I’m glad to get rid of such bunglers.”

“It’s not just these kids that made it hot for us!” Docker stormed. “If we’d known you were going to blow up that lab, we never would’ve gotten mixed up with you.”

The Hardys noticed that Paul Blum appeared startled at Docker’s words.

Frank spoke up boldly. “Sure. We all know you’re back of the sabotage. Who pays you for doing it?

And who’s your inside man at Elekton?”

Blum glared, then in a sinister tone replied, “You’ll never live to sing to the cops, so I’ll tell you. Several countries that want to stop United States progress in missiles are paying me. My friend in the plant is a fellow named Jordan.”

The saboteur revealed that his accomplice had first carried out smaller acts of sabotage, the ones which Chet had heard about from his father. It had been Blum himself who had driven the truck into the grounds and placed the dynamite in the laboratory. “Jordan and I gave your father the slip, then, too!”

“You guys can stand here and talk!” snapped Peters. “I’m going. You’d better take care of these Hardys.” He backed out of the cave and raced off.

The counterfeiters discussed heatedly whether “to get rid” of Frank and Joe immediately, or take “these kids” and dispose of them later.

“That’s your worry!” Blum said. “I’m taking off!”

“Oh, no, you’re not. You can’t leave us in the lurch.” Markel waved his gun meaningfully.

At that instant there was a crashing noise outside the cave. The three men swung around.

This was all the Hardys needed. They hurled themselves at their captors, forcing them backward onto the rocky beach. From the woods they heard Chet yell, “Here we come, fellows!”

Frank had tackled Blum, and Joe was wrestling with Docker on the beach.

Tony Prito yelled, “Got you!” as he took a flying leap at Markel and brought him to the ground. The older men, though strong, were no match for the agile Hardys and the furious onslaught of Chet and Tony.

Finally the struggle ended. The saboteur and counterfeiters were disarmed and lined up before the cave, their arms pinioned behind them by Joe, Chet, and Tony. Frank took charge of the revolvers. “Good work, you two!” he said to his friends. Chet, out of breath, grinned proudly. “I’m glad Tony and I stuck around when we saw these guys high-tailing it through the woods.”

Now Frank turned to the prisoners. “Okay. March!” he ordered.But before anyone could move, footsteps were heard approaching through the woods. A moment later Chief Collig and another officer appeared. With them, in handcuffs, was Victor Peters.

“Chief! Are we glad to see you!” Joe exclaimed.

The chief stared in amazement at the boys and their captives. “I got your message from Ken Blake,” he told Frank. “Looks as if you have your hands full!”

“Oh, we have!” Joe grinned, then, puzzled, he asked his brother, “What message?” “Just before I left the house I told Ken to call

Chief Collig if we weren’t back by eleven, and tell him where we had gone.”

While Blum and the counterfeiters stood in sullen silence, the four boys learned that Ken had called the chief just minutes after Fenton Hardy had left in the police launch in pursuit of Paul Blum.

“When we reached the mill we met this crook running out of the woods.” Chief Collig gestured toward the handcuffed Peters. “I recognized him from Chet’s description. When we found phony money on him, he told me where you were, hoping to get off with a lighter sentence.”

“You rat!” Docker’s face contorted with rage.

At that moment the group became aware of a police launch churning toward them, the beam from its searchlight sweeping the water. In the excitement, no one had heard the sound of its engine.

“Dad!” cried the Hardys, spotting the detective’s erect figure standing in the bow. Soon the launch was beached, and Mr. Hardy, with several officers, leaped ashore.

“Well,” Mr. Hardy said sternly when he saw Blum, “you won’t be escaping again.”

The captured lawbreakers were handcuffed and put aboard the launch. Mr. Hardy looked at his sons and their friends proudly. “You’ve done a yeoman’s job-on both cases, yours and mine,” he said.

After the police cruiser had departed, Frank and Joe led their father and the others into the mill cellar and showed them the secret room.

“This is all the evidence you need against the counterfeiters, Chief,” said Mr. Hardy. “I can see there are plenty of fingerprints on this equipment. We know some will match the one on the finger guard. Besides your evidence, boys, Ken’s testimony should be more than enough to convict them.”

“What about Jordan, Blum’s confederate at Elekton?” Frank asked.

Mr. Hardy smiled. “He was my big prize and I’m glad to say he is in jail!” The detective explained that further sleuthing had led to Jordan -and through him, Paul Blum. Mr. Hardy’s first break had come when he learned that one Elekton employee had seen Jordan going toward the laboratory building at closing time on the day of the explosion.

A police guard was assigned to watch the counterfeiters’ workshop and its contents. Then the four boys, Mr. Hardy, and the chief left the mill. Outside, they paused and looked back at the turning wheel.

Frank laughed. “Its signaling days are over.”

“Sure hope so,” Chet declared firmly. “No more mysteries for a while, please!”

Tony chuckled. “With Frank and Joe around, I wouldn’t count on it.”His words proved to be true. Sooner than even the Hardy boys expected, they were called upon to solve the mystery of THE MISSING CHUMS.

Now Joe turned to their plump friend. “Good thing you bought that microscope, Chet. We started to look for nature specimens and dug up the old mill’s secret!