"Say, Joe," he said, "maybe those men never went on that ferry at all. What say we go back there and look around?"

"Smartest idea you've had in a week." Joe dodged the pair of pajamas Frank hurled at him.

The two boys hurried to the breakfast table. They had hardly seated themselves when their 163 plump friend came through the doorway from the kitchen, glaring at them irately.

"Chet! Aren't you up kind of early?" Joe gibed his friend.

The other boy ignored the question. "I'm here to collect six dollars and thirty-five cents,"

he announced, without smiling.

"Wow!" cried Joe. "It sounds like a damage suit."

"Well, you might call it that," Chet said. "Anyway, you fellows have to fork over the money."

"And why?"

"Guess you forgot you were going to buy my dinner last night. On top of that you invited a bunch of people to have sodas, and-" Chet pointed his finger accusingly-"and you left me the check!"

Frank and Joe burst into laughter. "So that's it?" said Joe. "Why, you ungrateful wretch!

We left you with three of Bayport's most beautiful girls. What's six dollars and thirty-five cents compared to that?"

"It was a fine idea," said Chet, "only I didn't have any money with me. Had to borrow it from my sister. And did she kid me! Well, hand over the cash!"

"How about a compromise?" Frank asked, winking at Joe. "We'll pay two-thirds. In return for the rest you can have breakfast here and then go with us to nab that boat thief you're after. His name's Griff."

164 Chet's eyes opened wide. He forgot his troubles at once, and demanded to be brought up to date on news of his case. Upon hearing the account of Frank's adventure the evening before, Chet was eager to start off at once on the trail of the crook. Even Aunt Gertrude was amused at his refusal of a second helping of fried apple rings and corn bread.

By nine o'clock the three friends were on their way in the roadster. Frank made no stops until they came to a red traffic light some distance out of town. To the boys' amazement the signal began to hum peculiarly as it changed color.

"Another singing light!" Joe yelped. "Maybe ten minutes' drive from here------"

"Now listen, fellows," Chet interrupted, "you promised we'd hunt for that man Griff------"

"Okay," Frank said, and turned right.

Two minutes later they reached the public dock where the Hardys had lost the men the evening before. The boys jumped out and began to search in the roadway for clues.

Joe was the first to notice a narrow dirt road which branched off to the left along the water's edge. Judging from tall patches of gra.s.s growing in it, the road was not used often.

But there was a set of freshly made tire tracks.

"Come here!" the boy called excitedly, and pointed out his discovery. "These may mean something. Let's follow them!"

The three hopped into the car. Almost subcon165 sciously Joe glanced at his wrist watch, for he had become accustomed to timing their ten-minute rides from the "singing" traffic lights. Now he subtracted two minutes. Where would they be in eight more?

The road twisted and turned, finally coming out on the highway. Here the tire marks Frank had been following became intermingled with others.

"Now what?" Chet asked.

Joe was excited. "Go on, Frank!" he cried.

His brother obeyed. Two minutes later Joe called a halt and pointed.

"At last," he yelled, "we've solved it!"

"Solved what?" Chet demanded.

Words tumbled from Joe's lips. Just ahead was the Mead home, and they were ten minutes' drive from "singing" light number three! The boy was sure the secret panel was in the house, with Lenny Stryker and the nurse hidden in a room behind it.

"Gee, I'll bet you're right!" Frank agreed, his heart pounding. "I'd better hide the car in case anyone's watching. We'll go the rest of the way on foot."

"Now listen, fellows," Chet spoke up, "you're not going to get me mixed up in anything dangerous. I only came along to find that guy who got my money and then stole my boat."

"Chet's right," said Frank. "Suppose we go by 3 roundabout route to the Mead boathouse first and see if the dory's there?"

Chet trailed the Hardys through a patch of woods 166 to the water's edge. Then, creeping forward on their hands and knees, the boys made their way cautiously along the bank to the boathouse. Certain that no one had seen them, Frank stripped off his clothes and swam under the door of the building. Two minutes later he returned, his eyes shining excitedly.

"It's in there!" he whispered hoa.r.s.ely. "The dory with the funny Y on it!"

"Gosh! You mean it?" Chet whooped.

"Pipe down!" Frank hissed in a low voice. "Do you want to spoil everything? I saw something else, too."

As he pulled on his clothes, he revealed that on a bench inside the boathouse lay a crumpled piece of fresh wrapping paper from the Harlington drugstore. This evidence certainly linked the Mead house and the kidnapers!

"Say, Frank," said Joe suddenly, "remember when we were checking the switchboard and you got a shock that knocked you cold?"

"Sure do."

"When I was in the library, I heard a groan and raced back to you in the kitchen, thinking something had happened to you."

Frank looked startled. "I didn't groan. It was someone else!"

"Exactly!"

"Say, would you fellows mind telling me what you're talking about?" Chet demanded.

167 "Sure we'll tell you," Joe replied. "There's probably a hidden room in the Mead house.

You get into it through a secret panel. And behind that panel are two people who have been kidnaped."

Chet gulped. He hadn't meant to get so close to danger.

"It's time to act!" Frank said tensely. "Chet, you take the car and bring Dad here at once.

Tell him to give our special Hardy rap on the front door. Joe and I'll go inside the house and find the secret panel!"

Chet's teeth began to chatter. He did not relish his a.s.signment at all, but at least it was better than entering the mysterious house. He left at once, returning to the main road by the route through the woods. The boy sighed in relief as he reached the car and opened the door. Another twenty minutes and-----"Hold on!" a voice hissed in his ear.

Chet's heart almost stopped beating as a hand was laid on his shoulder. He was pulled around roughly and stood looking into a leering face.

Griff!

"At last we got you guys where we want you!" the man growled. "Come along! You're going to spend a few days with me. In the meantime, the boss will take care of those friends of yours, the Hardys!"

CHAPTER XX.

The Secret Pane!

"let's go!" whispered Joe, as soon as Chet was out of sight.

Using the boathouse, then shrubbery as cover, the brothers finally reached the Mead mansion without walking in the open. While Frank unlocked the front door, Joe kept a sharp lookout. They were sure not a person had seen them.

Noiselessly the door swung open. The boys stepped into the somber hall. This time, not wishing to be seen, they did not try the lights. Knowing their way around, the brothers quickly tiptoed from room to room. Satisfied that no one was inside, they began their hunt for a secret panel.

Not a word was spoken. Taking it for granted that the secret opening was somewhere near where Joe had heard the mysterious groan, the boys concentrated their efforts on the library. Dividing the work, they started to examine the walls inch by inch. After a while Frank looked at his watch and was startled to find he and his brother had been in the house two hours.

"Wonder where Dad is," he spelled out on his fingers.

Joe shrugged. In sign language he replied, "Why don't we call out the names of Lenny Stryker and Miss Johnson? We might save a lot of time."

Frank finally agreed. But, though the brothers shouted over and over again, there was no response.

"If there's any hidden room here, it must be soundproof," Joe concluded.

Once more the boys went to work looking for a secret panel. It was nearly an hour later when Frank, tapping, pushing, and pulling at bits of the heavily carved paneling near the fireplace, made a discovery. On a design of an oak tree with branches and leaves, one leaf proved to be movable. Beneath it was a metal disk.

"I've found something!" the boy cried, and Joe leaped across the room to see what it was.

"I wonder what this disk is," Frank mused. "It's not a keyhole."

Both boys endeavored to slide the metal disk aside, but were unsuccessful. Suddenly Frank had an inspiration. Pulling a small magnet from his pocket, he held it near the disk.

There was a definite attraction between the two pieces of metal, but there was no movement of the disk nor of the mechanism which was undoubtedly installed in the wall behind it.

170 "A bigger magnet might make this thing work," Joe suggested hopefully. "Maybe there's one hidden somewhere in the room."

He began to search. Frank too decided to look around. Inadvertently he dropped his magnet. To his amazement the small piece of steel began to crawl from the spot where it had fallen. In a moment it disappeared under the loose edge of the large rug. Quickly Frank pulled up the rug.

"Look!" he called excitedly.

Joe stared, dumfounded, at the moving magnet. Suddenly it stopped. Both boys fell to their knees and examined the floor. They were convinced a larger magnet must be hidden underneath. After a frantic search they found a floor board which was only laid in place.

Lifting it, the brothers yelped in delight. On a beam lay a large, powerful magnet.

"I'll try it against the wall!" Frank cried, and picked up the heavy piece of steel.

Hurrying to the metal disk, he directed the magnet toward it. The contact produced no results but the boys were not discouraged.

"It's got to do something!" Joe insisted. "Let's move the magnet back and forth!"

Frank did so. Suddenly the Hardys heard a click. At the same moment a large section of wall on which the oak was carved began to revolve around the trunk of the tree.

Frank and Joe held their breaths. As the opening became larger they found themselves peering into a room. Their hearts almost stopped beating. On a cot lay a man. Beside him, seated near a reading lamp, was the missing nurse, Miss Johnson!

Joe was first to step over the threshold of the secret panel. The woman looked up. As she recognized the boy, terror came into her eyes. Jumping from her chair, she cried out: "No! No! Don't come in!"

The warning was spoken too late. Someone leaped from a corner of the hidden room and clapped a hand over the nurse's mouth. Simultaneously a man in the library gave Frank a violent shove against Joe. The two boys tumbled head over heels into the room. They got up quickly, ready to fight. But it was no use. The men bound them hand and foot.

Griff and Jeff!

"We've got you at last!" Jeff panted. "An* just where we want you, too!"

In the meantime Miss Johnson had edged toward the doorway, hoping to escape and bring aid. But Griff caught the woman's arm.

"Oh, no, you don't!" he cried. "You're not going to get out of here."

She too was bound, and left on the floor. The two crooks surveyed their work, a satisfied grin on their faces.

172 Suddenly there came an agonized groan from the patient on the cot. Jeff began to laugh hoa.r.s.ely and then looked at the Hardys.

"You can have that sick boy to yourselves now," he jeered. "You been wantin' to find him!"

Griff picked up the magnet from the floor. "Come on, Jeff," he said. Turning to the others, he sneered, "You won't be able to get out of here-unless I let you out! And I don't intend to!"

The two men stepped through the opening into the library. As the Hardy boys watched in horror the secret panel closed.

They were prisoners!

CHAPTER XXI.

Trouble in the Dark.

Miss johnson's bonds had been tied hastily. With little effort she was able to remove them. Then quickly she unfastened the ropes which bound the Hardys. The boys dashed to the secret panel and endeavored to open it.