Every light of the camp was on as Rawson and his assistant approached. A shallow depression in the sand marked the place where the big casting had been. Beyond it a hundred feet was a black swarm of men that parted as the car drew near. They had been gathered about a figure upon the sand.

Dean sensed something peculiar about that figure as the big car ploughed to a stop. He leaped out and ran forward.

He knew it was Riley there on the ground, knew it while still he was a score of feet away. Only when he was close, however, did he realize that the body ended in two stubs of legs; only when he leaned above him did he know that the Irish foreman’s big frame had been cut in two as if by a knife.

The severed legs lay a short distance beyond the body; they had fallen side by side in horrible awkwardness, their stumps of flesh protruding from charred clothing and suddenly, shockingly, Rawson knew that the flesh of body and legs had been seared. The knife had been hot its blade had been forged of flame!

He heard Smithy cursing softly, unconsciously, at his side.

“The green light,” Smithy was saying in horrified understanding. “But who did it? How did they do it? Where did they go?”

“Quiet!” ordered Rawson sharply. He dropped to his knees beside the mutilated body. Riley’s eyes had opened in a sudden movement of consciousness.

The voice that came from his lips was a ghastly whisper at first, but in that stricken thing that had been the body of Riley, foreman of the night drilling crew, some reservoir of strength must still have remained untapped.

He drew upon it now. His voice roared again as it had done so many times before through the Tonah Basin camp. It reached to every listening ear where crowding men stood hushed and motionless; and the overtone of terror that altered its customary timber was apparent to all.

“Devils!” said Riley. “Devils, straight out o’ hell!... I saw ’em I saw ’em plain!... I shot as if hot lead could harm the imps of Satan....

“Oh, sir,” his eyes had found those of Dean Rawson who was leaning above “for the love of hivin, Mister Rawson, do ye be quittin’ drillin’. The place is damned. L’ave it, sir; go away....”

His eyes closed. But he started up once more; he raised his head from the sand with one final convulsive movement, and his voice was high and shrill.

“The fire! The fire of hell! He’s turnin’ it on me! God help....”

But Riley, before his failing mind could recall again that torturing jet of flame, must have slipped away into a darkness as softly enveloping as the velvet shadow world behind the low-hung stars. Rawson’s hand that felt for a moment above the heart, confirmed the message of the closed eyes and the head that fell inertly back.

He came slowly to his feet.

“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 titanic 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 coarse 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.

“Damn 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 masses 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 massive 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 passed 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 bumped 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 massive 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.

At the foot of the derrick was the hoisting shed. Except for that, there was clear sand for a radius of fifty feet around the derrick’s base. Dean was staring suspiciously at that open space almost directly underneath.

Moving sand! He hardly knew what he had seen at first. Then the sand at one point bulged upward unmistakably.

For one instant Dean’s thoughts shot off at a tangent. It was like the work of a huge gopher he had seen the little animals break through like that. Then the sand parted, and something, indistinct, blurred, dark against the yellow background, broke from cover.

Rawson swung the rifle’s muzzle over and down. Below him the vague shadow had moved. Dean caught the blurred mass beyond his sights, then swung the weapon aside. Who was it? He would have a look first.

The thin crack of his rifle ripped the silence of the sleeping camp. Dean had aimed to one side and he regretted it in the instant of firing. For, in the same second, there had come from the moving shadow the gleam of starlight reflected upward from polished metal.

Dean swung the rifle back. He fired quickly a second time. Beside him the big light hissed into action and the whole camp sprang to sudden, blazing light. And through the quick brilliance, more dazzling even than the white glare itself, was one blinding line of green flame.

Dean saw it as it began. It came from the dim shadow that had sprung suddenly into sharp outline as the big lights came on. He saw the figure. He sensed that it was a man, though he knew vaguely that the figure was grotesque and hideous in some manner he had no time to discern.

The thin line of green flame ripped straight out, swinging in a quick, sweeping trajectory, slashing through the steelwork of the great derrick itself!

Dean knew he was lost in the blinding instant while that fiery jet was sweeping in a fan-shaped sector of vivid green. A knife of flame! It had destroyed a man: it was now cutting down a framework of steel as well!

The derrick was falling as he fired again. There came a crushing jar downward as the metal melted and failed, and the wild outward swing in the beginning of the toppling fall. In the mind of Dean Rawson was but one thought: the sights and a something blurred beyond a trigger to be pressed.

He was still firing when the shriek of torn steel went to thundering silence, and even the lights of Tonah Basin Camp were swallowed up in the whirling night....