He had a vague recollection of imagining that step behind again, and he recalled at one point the almost welcome pain of a stubbed toe. But for the rest, he was too frightened to take it all in.

By the time the tenderfoot reached the summit of old Death Head and stood within fifty feet of the haunted tree, he was too frightened to move, and he almost expected to see the thing which he most feared. The sky was overcast again, but a dim white something towered before him—the haunted tree—and—and——!

But just at that moment the clouds broke, and the full moon, now all unveiled, flooded the scene with light.

Naked, stark, ghostly, the blasted pine-tree rose before him. With a sudden spasm at his heart Danny looked for the swinging dead man. But if anything unearthly hung from those bare white branches, his mortal eyes were spared the vision. And presently his awakening reason began to urge: "There are no such things as 'ghosts.'"

The next moment the young scout came fully to himself, and withdrew quickly from the all-revealing flood of moonlight to the friendly shadow of a low shrub. He began to peer sharply about. The growth around was ragged, with great spaces between. If there was anything here that a scout ought to note, the opportunity was ideal.

He must perform the duty for which he was here! His leader had told him to know the spot before he showed up in camp again.

Danny began skirting about in the shadows, getting every angle he could on the scene, and exploring adjacent wood lanes. It is true that he kept well away from the haunted tree, but he came back to its vicinity every now and then. And each time as he came he managed to force himself to approach it closer.

Nearer and nearer he got to it, and then, suddenly, he heard issue from somewhere in its branches a low, sighing moan. Danny thought he would drop in his tracks, but he did not. Instead, he stood as still as death and listened.

That moan again! Every time a gust of wind came, the dim, weird sound trembled along the night.

The moon was shining brilliantly now. Danny stood staring at the haunted tree.

All at once he crept forward, sharply intent on something.

What was that straight black line against the sky? Where did it come from?—that haunted tree?

Another moment and Danny was at the foot of the ghostly pine-tree, staring upward at the crisscross of its naked branches.

There was no swinging dead man there, but there was something—at the top!

Danny dropped to the ground and retreated a little on all fours for a better view-point. 'Way up, two parallel black bars rose against the sky.

A scout must keep his head!

Now, no boughs of a tree ever grew that straight! And what were those orderly black lines which extended from one bar to the other?

That moan again!—or—or was it the sound of a wire, played upon by the wind?

Danny shifted his position again.

Yes, that black line across the sky connected directly with the queer something in the tree top.

"Wireless!" said the scout's head to him.

Danny stood up. All childish fear of a swinging ghost had dropped away from him. He had not the slightest inclination now to cry like a baby about anything.

He was a scout on duty!

Another moment and he was creeping, velvet-footed, through the woods, following that black line as it led away from the haunted tree. At the other end of it must be a receiving-station!

And it was no easy task which his duty set him. Over sharp rocks and through tangled briers that black line led him on. Sometimes the moon would desert him and he would lose the clue for a while. Sometimes he would be forced to abandon his clue to skirt around an insuperable barrier. But he always came back to it, always pressed on.

On and on! And then, suddenly, the line disappeared. It ended, or seemed to end in a large pile of boulders which clung to the mountainside. The undergrowth was dense here.

Danny circled about the spot. Yes, the wire stopped here. He began creeping through the underbrush—feeling his way along the side of a great boulder.

Suddenly his hand touched—nothing!

The scout stopped and thought. There was some sort of break in the rock here.

Danny had a flashlight in his pocket which he had been too cautious to use. He thought of it now, and hesitated. Then he slipped it out and pressed the spring.

Before him was what seemed the door of a cave. He looked closer. Yes, the wire led into the cave. Darkness, again, for he was afraid to use his light any longer.

Danny dropped to his all-fours and crept into the black hole. A floor of soft sand helped him to advance noiselessly. After a few yards the scout reached a turn in the rocky passageway, and——

His eye caught a big, black-hooded shadow humped over a point of light!

Danny withdrew quickly behind the sheltering turn in the wall, and crouched in the sand, dead-still. But his blood was up. He took a second look.

A man was sitting over some sort of instrument, and over his ears were cups, something like Danny had seen worn by the girl at the telephone central station. The one point of light in the big dark recess was turned on a note-book under the man's hand.

The young scout drew back, and crept silently out of the cavern.

Out under the stars again, and this time with his blood on fire! A spy, a German spy sat in that cave and sent messages——!

Only yesterday a fleet of transports had slipped out of the harbor, with thousands of American soldiers on board—submarines—sea-raiders!

But a scout must keep his head.

Help? Which way could help be found? The boys were scattered, McKenzie would not be in camp. Nobody knew when to expect Mr. Gordon.

Which way? Which way? Oh, yes, down over the drop of the cliff to the south yonder was the mountain wagon road by which their scouting party had ascended that afternoon. If he could get to the road he could find somebody somewhere—surely, there were a few inhabitants hereabouts!

That German was sending wireless messages right this minute—— Yes, the shortest way to the road was the only way for a fellow to take now! And Danny took it.

When he reached the cliff, spent and sore, a new difficulty presented itself. A sheer fifty-foot drop still separated him from the road. He crept along the edge searching for a footing by which to descend, and presently found one that looked possible. There were broken, shelving places here, and tufts of growing things down the face of the dizzy wall.

Danny began to climb down. But he found it harder than he had thought, and at times he was a mere human fly clinging to a rock wall.

A man was sitting over some sort of instrument.

Nearly down—only about fifteen feet more! But at that moment the human fly's hold crumbled under his clinging fingers, and he dropped. It ought not to have been a bad fall, but the trouble was a loosened rock followed, and came down on one arm as its owner lay prostrate on the ground.

Danny lay very still for a few moments, looking at the stars and thinking of—nothing!

Then presently the sound of human voices came to him from somewhere out of the night.