"Oh!" he exclaimed as Coles Masters shoved the door open, "it's you. I'm glad you're here. Got something I want to look into. Want to bad. Mind if I take an extra hour?"

"Nope."

"All right. See you later." With a bound he was out of the door and down the stairs.

"That boy," muttered Coles Masters, with a grin, "will either die young or become famous. Only Providence knows which it will be."

Curlie did not leave the elevator at the first floor. Dropping down to the sub-bas.e.m.e.nt, he wound his way in and out through a labyrinth of dimly lighted halls, at last to climb a stair to the first bas.e.m.e.nt.

Then, having pa.s.sed into his accustomed eating place, he paused long enough to purchase a Swiss cheese sandwich, after which, with cap pulled well down over his eyes, he made his way up a second flight of stairs into the outer air.

He shivered as he emerged into the open street. Whether this chill came from the damp cool of the night or from nervous excitement, he could not tell. The memory of the whispered warning bore heavily upon his mind.

Turning his face resolutely in the direction of the hotel, he walked three blocks, then hailed a pa.s.sing taxi. When the taxi dropped him, a few minutes later, he was still four blocks from the point of his destination. Covering this distance with rapid strides, he came to the rear of the hotel. There, dodging past a line of waiting taxis, he came at length to a dark corner where a stone bench made an angle with the wall of a building directly behind the hotel.

Crouching in this corner, he glanced rapidly from right to left to learn whether or not his arrival had been detected. Satisfied that for the moment he was safe, he cast a glance upward to where the aerials of the radiophone glistened in the moonlight. From that point he allowed his gaze to drop steadily downward until it reached the windows of the sixteenth floor. There it remained fixed for a full moment.

There came from between his teeth a sudden intake of breath.

Had he seen some movement at the window to the right of the wires that led to the aerials? He must see, no matter how great the risk.

Drawing a small pair of binoculars from his pocket, he fixed them on the spot. He then turned a screw at the side of the binocular and suddenly there appeared upon the wall of the building a round spot of brilliant light. The size of a plate, this mysterious spot moved rapidly backward and forward until it at last rested upon the wires by the window.

"Ah!" came in an involuntary whisper from the boy's lips.

A hand, the slender, graceful hand of a girl had been clearly outlined against the wall. Quickly as it had been withdrawn, Curlie had seen that between the thumb and finger of that hand was the end of a wire.

"Been tapping the aerial. A girl!" he muttered incredulously. "And it was she who whispered to me out of the night."

He had been crouching low. Now he rose, stretched himself, pocketed his instrument and was about to make his way out of the yard when, with the suddenness of a tiger, a body launched itself upon his back.

So unexpected was the a.s.sault that the boy's body closed up like a jack knife. He fell, face down, completely doubled up, with his face between his knees.

"Now I got yuh!" was snarled into his ear. The weight on his back was crushing. He could scarcely breathe.

"You--you have," he managed to groan.

"You'll come along," said the voice.

Curlie did not speak nor stir. The weight was partly lifted from his back. The man had dropped one foot to the ground.

Now Curlie, had he been properly exercised for it when he was a child, might have turned out a fair contortionist. He was exceedingly slim and limber and had learned many of the tricks of the contortionist. He had done this merely to amuse his friends. Now the tricks stood him in good stead.

He did not attempt to rise by straightening up, as most persons would have done. When the pressure grew less, he lay still doubled up, face down upon the ground.

This gave him two advantages. It led his a.s.sailant to believe him injured in some way and at the same time left him in position for the next move.

When the pressure had been sufficiently removed for his purpose, he took a quick, strong breath, then with a rush which set every muscle in action, he thrust his head between his knees, gripped his own ankles and did a double turn over which resembled nothing so much as a boulder rolling down hill.

The next instant, finding himself free, he sprang to his feet, dodged behind a taxi, shot past three moving cars, leaped to the pavement, skirted a wall, then dodged into an alley.

Down this alley there was a doorway. Into the shadow of this doorway he threw himself. There was a hole in the wooden door. A hook could be reached through the hole. The hook quickly lifted, he found himself inside a narrow court at the back of a large apartment building. There was a driveway from this court into the street beyond.

a.s.suming a natural pace, he made his way down this driveway and out into the street where, with a low whistled tune, he made his way back toward the heart of the city. Five blocks farther down he paused to adjust his clothing.

"Wow! but that was a close one," he muttered. "Don't know who my heavy friend was but he sure wanted to detain me for some reason or other. But say!" he mused; "how about that girl? Hope I didn't get her in bad by flashing that light on her hand.

"But then," he thought more soberly, "perhaps she is the princ.i.p.al bad one. Perhaps she is whispering on 200 just to mislead me. Who knows?

You've got to be wise as a serpent when you play this game, that's what you've got to be. There's just two kinds of radio detectives, the quick and the dead." He chuckled dryly.

"Well, I guess Coles Masters will think I'm one of the dead ones if I don't rush on."

Hurrying to the next street, he boarded a car to make his way back to the secret lower room.

During his absence things had been happening in the mysterious radio world that hangs like a filmy ghost-land above the sleeping world.

CHAPTER IV

A GAME FOR TWO

As Curlie slipped noiselessly through the door into the secret tower room, he was seized by the arm and dragged into his chair.

"Man! where have you been?" It was Coles Masters. He spoke in an excited whisper. "Listen to that! It's the second message. He'll repeat it again. They always do."

As Curlie listened, his face grew grave with concern. The message came from the head station of the radiophone secret service bureau. That station was located in New York. The message was a reprimand. Kindly, friendly but firmly, it told Curlie that for two nights now someone in his area had been breaking in on 600. Coast-to-ship messages had been disturbed. Once an S. O. S. from a disabled fishing schooner had barely escaped being lost. Something must be done about it at once! By Curlie!

In Chicago!

With parted lips and bated breath Curlie listened to the message as it came to him in code. Then, with trembling fingers, he adjusted a lever, touched a b.u.t.ton, turned a screw and dictated to a station in another part of the city his answering O.K. to the message.

"Of course," he said to Coles, as he lifted the receiver from his head, "that means that this fellow that races all over the map has been at it again to-night."

"About an hour ago," said Coles, wrinkling his brow.

"What did you do about it?"

"What was there to do? I tried to locate him. He danced about, first here, then there. I marked his locations. They were never the same.

See," he pointed to the map. "I numbered them. He spoke from five different points."

"What did he say?"

"It's all written down there," Coles motioned to a pad. "Can't make head nor tail to it. Something about a map, an airplane, a boat and a lot of gold."

"What kind of voice?"

"Sounded young. Some boy in late teens, I'd say. Though it might have been a girl. She might have changed her voice to disguise it. You can't tell. Had two cases like that in the last three weeks. You never can tell about voices."