Joe steered the Sleuth Sleuth across the bay. As he neared the opposite sh.o.r.e, he called across the bay. As he neared the opposite sh.o.r.e, he called attention to the property which lay just ahead.

30 "It's the Mead place," he explained to Chet. "We haven't had time to tell you about the mystery we ran into this morning in connection with it."

Chet listened wide-eyed as he was told about the car which had lost a wheel, the driver who had used the name of a dead man, and the unusual key which was supposed to fit a door without a keyhole. At this point in the story Frank suddenly cried out: "I've lost it!"

"Lost what?" Chet asked.

"The key! The key the man gave us!" Frank was frantically going through his pockets.

Joe stared at his brother, unbelieving. Finally he said, "Maybe you left it at home."

"No. I wish I had." Frank groaned. "I guess it fell from my pocket when we dived out of Chet's boat."

"What'll you do?" Chet asked.

"I don't know."

"Maybe the key wouldn't open the Mead doors anyway," said Joe consolingly. "Chief Collig didn't think it would, remember?"

"But just the same, I wish I hadn't lost it," said Frank.

The Hardy boy was worried. If the man who had given the key to him should come back for it, the situation would be very embarra.s.sing. Chet tried to make Frank feel better by saying a door without a keyhole certainly did not need a key, so why worry about it?

31 "I'd like to see those doors," he added. "Let's tie up and have a look."

Joe cut the motor and allowed the Sleuth Sleuth to drift to sh.o.r.e. Here he made it fast to the to drift to sh.o.r.e. Here he made it fast to the little platform adjoining the Mead boathouse. The boys got out and walked to the side door.

"Yipe!" cried Chet. "It's true! You know, fellows, I didn't believe you when you said there wasn't a keyhole in any of the doors here. But now-gee whiz, how do you get the thing open?"

"If we knew, we'd have been inside long ago," Joe answered him.

"Boy, this is a mystery," remarked Chet. "Let's go to the house."

The Hardys led the way to the mansion. Their friend gaped blankly at the heavily carved rear door.

"Are all the doors carved?" he asked.

"Yes. Each has a different design, though. But not one of them has a keyhole or a k.n.o.b,"

Joe told him. "Queer, eh?"

As the boys rounded the house to inspect the front door, they heard a car coming along the driveway. Frank and Joe thought it might be the man who called himself John Mead, so they waited. To their amazement, when the automobile rounded the winding approach to the house, its driver jammed on the brakes, and backed around the curve.

"Well, what do you make of that?" cried Joe.

"Looks as if somebody didn't want to meet us," Frank replied.

32.

He ran forward, trying to catch a glimpse of the driver or his license plate, but the car was almost out of sight. When the driver reached the highway, he turned in the direction of Bayport.

Frank glanced at his wrist watch, for Mr. Hardy had taught his sons always to note the exact time any unusual circ.u.mstance occurred.

"What time is it?" Chet asked.

"Four-thirty."

"Yipe!" squealed the stout boy. "I'm supposed to meet my mother at five o'clock!"

The Hardys smiled. Poor Chet! His memory played him one trick after another! The three boys hurried to the boathouse and jumped into the Sleuth. Sleuth. Joe sent it skimming Joe sent it skimming across the water. Ten minutes later Chet alighted.

"See you tomorrow, fellows," he called. "And don't forget to work on my case."

As the Hardys tied up their boat, they suddenly realized their chum had not given them a detailed description of the stranger who had sold him the dory. A stocky man of thirty, who did not smile, was not much help in trying to locate the culprit.

Reaching home, the brothers found their mother had returned. She was in the kitchen mixing batter for m.u.f.fins, and from the oven came the appetizing odor of roast beef. Frank and Joe hugged her affec' tionately, complimenting her on the good dinner.

"Was the hug for me or for the dinner?" Mrs. Hardy teased them.

33 "Oh, Mother," Mother," her sons chorused, and Joe added, "You know you're the best mother in her sons chorused, and Joe added, "You know you're the best mother in all the world. But I wish you wouldn't keep so many secrets to yourself."

"Secrets?" Mrs. Hardy asked, puzzled.

From the two boys she learned the story of Mike Matton, and how he had been about to change the back-door lock when they had suddenly stopped him.

"Well, I'm certainly glad you did," their mother said. "There must be some mistake. I didn't phone Ben Whittaker."

"We didn't think you had," said Frank. "I'm going right down there and find out what that fellow Matton was talking about. Come on, Joe."

Ten minutes later the boys came to old Ben Whit-taker's store. The proprietor was just closing his shop, but he smiled at the brothers and let them in.

"Has Mike Matton gone for the day?" Frank asked quickly.

"Yes. As a matter of fact, he didn't come back here after he went out on some errands a few hours ago."

"Mr. Whittaker, have you found him to be entirely honest?" Joe startled the man by saying.

"Why-er-yes. I guess so. What's on your mind, son?"

The Hardys told the elderly man the incident of Mike Matton and the back-door lock, and how their mother had not telephoned to have it changed. Ben 34 Whittaker became concerned at once. He went into his shop to look at the order pad.

"Yes, here it is," he said. "Just like I told you on the phone this afternoon."

"May I see it?" Frank requested.

Ben Whittaker handed over the pad. On it was their own name and also that of a family named Ec-cles. Frank suggested that he telephone Mrs. Eccles to see if she had left an order to have her lock changed. The shop owner was too nervous to make the call and asked the boy to do it. Frank got Mrs. Eccles on the wire, but he had barely started speaking when there came a torrent of words from the other end.

"So you're the one who's responsible for running off with my expensive lock, are you?

Well, you bring it back and bring it back in a hurry," Mrs. Eccles ordered. "My husband's furious about it. We didn't order it changed, and this cheap lock your man put on is a disgrace!"

"Please, Mrs. Eccles," Frank pleaded, "there has been a mistake, and Mr.

Whittaker------"

"I'll say there's been a mistake," the woman interrupted. "And it's got to be rectified at once. You tell Mr. Whittaker to be up here first thing in the morning to put back my rare antique door lock or else------*"

She hung up. Frank turned to Mr. Whittaker, and repeated the conversation. The elderly man paced up and down, completely baffled. Mike Mat35 ton had brought excellent references; surely the fellow was honest.

"Where does he live?" asked Joe, who did not share Ben Whittaker's feeling of trust in the young locksmith.

"In a boardinghouse on Dover Street. I'll get him on the phone."

The woman who answered the telephone said Matton had not been there since morning, and had left word he would be away until late that evening. Old Mr. Whittaker's momentary hope of straightening out the situation at once faded. The Hardys felt they could do nothing more, so with a wish that everything would turn out all right, they said "Good night."

Both boys felt uneasy, and were suspicious of Mike Matton. One mistake might occur, but hardly two of the same kind.

"What I can't understand," said Joe, "is why our house and Eccles' were picked out.

Theirs had a valuable lock that might be worth stealing, but ours hasn't."

"It's a puzzler, all right," Frank agreed. "I'm still inclined to my first idea that Matton never intended to put a new lock on our door; he just planned to get into the house and rob us! But he covered himself nicely with that false order on the phone pad."

When the boys reached home, they learned that Mr. Hardy would not return until the next morning. Mrs. Hardy and her sons sat down to dinner, and 36 during the meal Frank and Joe told her everything that had happened to them during the day.

"I'd say," their mother laughed at the end of the recital, "that you are on the threshold of two or three mysteries. Which one of them will you work on?"

Her sons grinned, thus giving her their answer. They would work on all of them!

"One thing I want to do early tomorrow morning," Frank said, "is dive for the lost key. I meant to ask old Mr. Whittaker if he knew anything about the Mead place, but I didn't have the heart to. The poor man was too upset."

"Well, I suppose you'll have another big day tomorrow," Mrs. Hardy smiled. "In that case you'd better get to bed early."

Frank and Joe followed this advice, and Mrs. Hardy herself retired at ten o'clock. It was two hours later that she came to the boys' room and awakened them, saying the front-door bell had rung. Since her husband had received the threatening letter that morning, he had requested her not to go to the door alone at night.

"Ill see who it is," offered Joe, jumping from bed.

As he spoke, the bell rang again. This time the caller kept his finger on the b.u.t.ton. Frank and Joe grabbed up robes and slippers as they hurried to answer the summons. Mrs.

Hardy, on the stairs right behind them, kept warning the boys to be cautious. Before opening the door, Frank snapped on the porch light and looked out.

37 A strange woman stood there, fidgeting nervously. She wore a faded pink hat over her straggly hair. A black coat had been thrown carelessly over her slim shoulders. As the boy slowly opened the door, the caller pushed it in excitedly.

"Where's Mr. Hardy?" she cried in a shrill, hysterical voice. "I got to see him right away!"

CHAPTER V.

The Traffic Signal Clue.

mrs. hardy turned on a light in the living room and led the distraught caller to a chair.

"Please sit down," she said kindly. "Mr. Hardy isn't here at the moment, but perhaps we can help you."

"No, no. Only Mr. Hardy can help me!" the woman cried. "Maybe you think I don't have enough money to pay a good detective, but I got a little put aside. And I'll spend every cent of it on my boy Lenny if I have to!"

"Lenny is your son?" Frank asked.

"Yes, and a good boy. In all his eighteen years he never did no wrong, but them racketeers-they're the cause o' his downfall!"

"Have you been to the police?" Joe asked.

The woman gave a shriek. "Police? I should say not. They wouldn't understand. They'd put my Lenny in jail. That ain't never happened to a Stry-ker and it ain't goin' to happen now!"

39 As the woman paused for breath, Frank inquired if she was Mrs. Stryker. The caller nodded, adding that she was a widow-a hard-working one too-and Lenny was her only child.

"I'm sorry you're having trouble," said Mr& Hardy. "When Mr. Hardy returns tomorrow------"

The caller wrung her hands. "Tomorrow? I was hopin' he could do somethin' tonight. You see, I got a message from Lenny just a little while ago, and somethin' ought to be done right away. He said the gang nearly got caught, and he'd been shot in the leg."

"Shot!" chorused the three Hardys, and Frank added, "What Lenny needs is a doctor."

"No, no! He needs a detective!" Mrs. Stryker moaned.

The woman explained she did not know where Lenny was, and was afraid he would not receive proper care. "That's why I want Mr. Hardy to find him."

"Did your son give you any hint about where he is?" Joe asked eagerly.

"I think so. I'll tell you all I know."

The boys leaned forward in their chairs, waiting intently for the woman's story. She told them her son had acted mysteriously of late, and that she had suspected he had fallen into bad company. He had gone out earlier that night. Then, at eleven-thirty he had telephoned, saying he had been shot.

"Lenny mumbled some funny words," Mrs. Stry40 ker explained. "Two of 'em sounded like 'secret panel.' Then the connection was cut off."

Secret panel!

Frank* and Joe looked at each other. It was a clue, all right, but just where would one start to investigate it? Mrs. Stryker, though quizzed for fifteen minutes, could shed no more light on the subject. At last she stood up to go, disappointed because the Hardys could give her no help.