"Keep the floods on!" he ordered. "Take command of the armed guard, Smithy; keep the whole camp patrolled."

Then to the men:

"Boys, Riley was wrong. He believed what he said, all right, but Smith and I know better. Don't worry about devils. These're just some dirty, skulking dogs who got away with murder this time but who won't do it again. We know where they're hiding. I'm checking up on them right now. After that you'll all get a chance to square accounts for poor old Riley!"

"But the casting!" Smithy protested when he and Rawson were alone.

"You can't explain that disappearance so easy, Dean."

"No, I can't explain that," Rawson's words came slowly. "They've got something that we don't understand as yet--but I'm going to know the answer, and I'm going to find out to-night!"

He was seated behind the wheel of his old car.

"I'm as good a desert man as there is in this crowd," he told Smith.

"And it's my fight, you know. I'm going alone. But there'll be no fighting this trip; I'll just be scouting around."

He leaned from the car to grip Smithy's shoulder with a hand firm and steady.

"You didn't see the crater when the show was on. You think that I'm crazy to believe it, but up in that crater is where I'll find the answer to a lot of questions. Lord knows what that answer will be.

I've quit trying to guess. I'm just going up there to find out."

He was gone, the rear wheels of the car throwing a spray of sand as he started heedless of Smithy's protests against the plan. Rawson was in no mood to argue. He must climb the mountain while it was night; under the sun he would never reach the top alive. He would go alone and unseen.

He swung wide of the deserted town at the mountain's base. The spectral walls of Little Rhyolite still showed their empty windows that stared like dead eyes, and the man guided his car without lights along a hidden stretch of hard, salt-crusted desert. He felt certain that other eyes were watching.

He began his climb at a point five miles away. The slopes that seemed smooth and hard from a distance became, at closer range, a place of wind-heaped, sandy ash, carved and scoured into fantastic forms. But its very roughness offered protection, and Rawson fought the dragging sand, and the gray, choking ash that dried his throat and cut it like emery, without fear of being observed.

He fought against time, too. Above Little Rhyolite, whatever mysterious men were making the ascent would find the going easy. There were windswept areas, long fields of pumice; a man could make good time there. Rawson had none of these to aid him. He cast anxious glances toward the eastern sky as he struggled on, till he saw gray light change to rose and gold--but he stood in the t.i.tanic cleft in the crater's rim as the first straight rays of the sun struck across.

The volcano's top had been stripped clean by the winds of countless years. Rocks, black, brown, even blood-red, were naked to the pitiless glare of the sun. Their colors were mingled in a weird fantasy of twisted lines that told of the inferno of heat in which they had been formed.

They towered high above the head of Dean Rawson as he stood, panting and trembling with exhaustion. The cleft before him had become enormous: it was a canyon, half filled with pumice and coa.r.s.e ash.

Rawson stood for long minutes in quiet listening. At the canyon's end would lie the crater, and in that crater he would find.... But there was no slightest picture in his mind of what he might see. He knew only that he himself must remain unseen. He went forward cautiously.

Rocky walls; a floor of sand where his feet left no mark. He was watching ahead and above him. His gun was ready in his hand; he did not propose to be ambushed. He moved with never a sound.

The silence persisted; no living thing other than himself lent any flicker of motion to the scene. Not even a lizard could hope for existence amid these dead and barren heights. He was alone--the certainty of it had driven deeply into his mind before the canyon end was reached. And, desert man though he was and accustomed to traveling the waste places of the earth, Rawson learned a new meaning and depth of solitude.

Here was no voiceless companionship of trees or brush or cactus; no little living things scuttled across the rocks--he was alone, the only speck of life in a place where life seemed forbidden.

So sure of this was he that he stepped boldly from the canyon's end.

He knew before he looked that he would see only more of the same desolation. And his mind was filled equally with anger and disappointment.

Something was opposing him! Something had come into their camp--had killed old Riley. And he, Rawson, had been so sure he would find traces here that would allow him to give that opposing force a name....

He stared out from the rocky cleft into a sun-blasted pit. Already the rising sun was pouring its energy ever the jagged rim of bleak rocks and down into the vast throat, choked and filled with ash.

It sloped gently from all sides, the gray-brown powder that had been coughed from within the earth. It made a floor where Rawson could have walked with safety. But he did not go on.

"d.a.m.n it!" he said with sudden savagery. "What a fool I was to think of finding anyone here. Who would ever pick out a spot like this for a base of operations?"

He stared angrily at the floor of ash, at the black, outcropping ma.s.ses of tufa. He was angry with himself, angry and baffled and tired from his climb. Far down in the vast, shallow pit blazing sunlight glinted from ma.s.sive blocks whose sides were mirror-smooth. A whirl of wind eddied there for a moment and lifted the dust into a vertical gray column--the only sign of motion in the whole desolate scene.

Rawson turned and tramped back toward the long hot descent to the floor of the Basin.

He tried to maintain an air of confidence before the men. He kept them busy placing and stacking materials; to all appearances the work would go on despite the mysterious happenings of the night.

Dean even prepared to resume drilling operations. He sent down another bailer on the end of the ten-mile cable, but he left it there; he did not care to raise it and risk more inexplicable results with the consequent destruction of the men's morale.

"Too late to do any more," he said to Smithy that afternoon. "We'll drop all work--let the men get a good night's sleep. I'll take guard duty to-night, and you can run the job to-morrow."

There were men of the drilling crew standing near, though Rawson was handling the hoisting drums himself. A ratchet release lever hooked its end under a ring on Rawson's hand and pinched the flesh. Dean made this an excuse for waiting a moment while the drillers walked away.

"Ought not to wear it, I suppose," he said, and dabbed at a spot of blood under the gold band. "But it's an old cameo--it belonged to my Dad."

He was showing the ring to Smithy as the men pa.s.sed from hearing.

"Don't want to be seen talking," he explained tersely. "Mustn't let the men know we are on edge--they're about ready to bolt. But you be ready for a call. Have your men armed. I am looking for more trouble to-night."

The two were laughing loudly as they followed the men toward the building where the cook was banging on an iron tire that served as a bell.

Some three hours later Rawson was not smiling as he climbed the steel ladder of the great derrick; he was grimly intent upon the job at hand.

All thought of his drilling operations had gone from him. He was not anxious about the project. This was merely an interruption; the work would go on later. But right now there was an enemy to be met and a mystery to be solved.

A rifle slung from his shoulder b.u.mped against him satisfyingly as he climbed. A man was on duty at a master switch--he would flood the camp with light at the rifle's first crack.

Dean seated himself at the top of the derrick. The cylinder of a huge floodlight was beside him. Beyond was the ma.s.sive sheave block; the cables ran dizzily down to the concrete drilling floor so far below.

And on every side the quiet camp spread out dark and silent in the night. Dean surveyed it all with satisfaction. Nothing would get by him now.

But his further reflections were not so satisfying.

"Who did it? How? Where did they go?" He was echoing Smithy's questions and finding no ready answers. And that flame-thrower that had cut down old Riley--how was that worked? Its one green flash had been almost instantaneous.

He was puzzling over such futile questioning when he saw the first sign of attack.