It was shortly after midnight when a persistent nightmare aroused Don Foster from sleep. For a moment he lay drowsily in his blankets there on the sand, with memory of the nightmare still vivid.

It had been a monstrous flying thing like a giant blue-bottle fly that he had been battling in his sleep. Memory of the thing’s high-pitched, droning buzz still rang in his ears. Then abruptly he realized that the peculiar buzzing was no mere echo of a nightmare. It was an actual sound that still vibrated from somewhere within the camp.

[Illustration: ... Yet that thread held.]

Startled into full awakening, Foster propped himself up on one elbow. The sound was penetrating, but not particularly loud. He was apparently the only one whom it had awakened. In the gray gloom of the desert starlight he saw the blanket-shrouded figures of the rest of the men still deep in slumber.

He realized the source of the sound now. It came from inside the black walls of Layroh’s tent, pitched there in its usual isolation on a slight rise fifty yards from the sleeping group. Foster grunted disgustedly to himself. More of Layroh’s scientific hocus-pocus! The man seemed to go out of his way to add new phases of mystery to this crazy expedition of his through the barren wastelands of the Mojave.

For a solid week now they had been working their way back and forth over a thirty-mile stretch of desert, while Layroh labored with his intricate instruments searching for something known only to himself. Whatever reason Layroh had for recruiting a party of fifteen to accompany him was still a mystery. So far the men had done practically nothing except trail along after Layroh while he worked with his apparatus.

It was a state of affairs that caused the men little worry. As long as they had enough to eat they were quite content. They were down-and-outers, all of them, human derelicts recruited from the park benches and cheap flop houses of Los Angeles. They had only one thing in common: all of them were large and powerful men.

Don Foster was the youngest of the fifteen, and the only college man in the group. A succession of bad breaks had finally landed him broke and hungry on a park bench, where Layroh found him. Layroh’s offer of ten dollars a day and all expenses had seemed a godsend. Foster had promptly jumped at the offer. Layroh’s peculiar conditions and rules had seemed trivial details at the time.

Foster scowled as he lit a cigarette and stared through the gloom at the violet-lighted tent from which the disturbing sound still came. Seven days of experience with Layroh’s peculiarities had begun to make them a little irritating. His sternly enforced code of rules was simple enough. Never approach Layroh unless called. Never touch Layroh’s instruments. Never approach Layroh’s tent. Never ask questions.

Layroh neither ate with the men nor mingled with them in any way that could possibly be avoided. As soon as they made camp each night he set up his small black tent and remained inside it until camp was broken the next morning. No one knew whether the man ever slept. All night long the violet light glowed inside the black tent. The men had wondered about the unusual color of that light, then had finally decided it was probably something required by the same eye weakness that made Layroh wear heavily smoked goggles, both day and night.

Strange sounds in the night as Layroh worked with his apparatus in the black tent were nothing unusual, but to-night was the first time that Foster had ever heard this peculiar whining buzz. As he listened it rose in a sudden thin crescendo that rippled along his spine like a file rasping over naked nerve-ends. For one shuddering second there seemed to be an intangible living quality in that metallic drone, as though some nameless creature sang in horrible exultance. Then abruptly the sound ceased.

Foster drew a deep breath of relief and ground his cigarette into the sand beside him. Better try to get to sleep again before Layroh started some new disturbance with his infernal apparatus.

He was just settling down into his blankets when a movement in the tent drew his attention back to it. Layroh was apparently changing the position of the violet light, for his tall figure was suddenly silhouetted against the tent wall in sharp relief.

Foster started in surprise as another figure loomed darkly beside that of Layroh. For a moment he thought that the unprecedented had happened and some member of the expedition was inside those jealously guarded tent walls with Layroh. Then he saw that the figure must be a mere trick of the shadows cast by the moving light upon some piece of luggage. It looked like the torso of a man, but the head was a shapeless blob and the arms were nothing more than boneless dangling flaps. A moment later the light moved on and both shadows vanished.

Foster grinned sheepishly over the momentary start the distorted shadow had given him, and determinedly rolled himself in his blankets to sleep. It was after sunrise when he awoke. The rest of the camp was already up, but there was one member of the party missing.

Jeff Peters’ empty blankets were still spread there on the sand, but no one had seen the big Negro since the camp turned in the night before. The expedition’s daily travels under the blazing sun of the Mojave never had appealed particularly to Jeff, and he had apparently at last made good his repeated threats to desert.

The men were just getting up from breakfast when Layroh finished packing his tent and apparatus in his sedan, and started down toward the camp. As usual, he halted some five yards away from them, standing there for a moment in stony silence.

Physically, the man was a giant, towering well over six feet in height. On several occasions when the expedition’s cars had stalled in deep sand he had strikingly demonstrated the colossal strength in his tall body.

His aquiline features, his red-bronze complexion, and his long black hair, were all suggestive of Incan or Mayan ancestry. No one had ever seen any trace of feeling or emotion upon his impassive features. Foster would have given a good deal for just one glimpse of the eyes hidden behind the dark-colored goggles. In their depths he might be able to find some reason for the tingling surge of nameless dread that Layroh’s close approach always inspired.

Layroh noted Jeff Peters’ absence at once. “We seem to have our first deserter,” he commented evenly. His voice was as richly resonant as the tone of some fine old violin. He hesitated almost imperceptibly between words, like one to whom English was not a native tongue.

“It does not matter,” he continued indifferently. “We can spare one man easily enough. To-day we shall continue toward the east. Pack the truck at once. We are ready to start.”

Without waiting for an answer, he turned and strode back to the sedan. A curious thought struck Foster as he stared after Layroh’s retreating figure. What if the oddly distorted shadow he had seen against the tent wall last night had really been that of a man--had been that of Jeff Peters?

For only a moment did Foster mull over the idea. Then he promptly dismissed it as being absurd. He could imagine no possible reason for Jeff Peters being in Layroh’s tent in the middle of the night. The shadow had been only remotely like that of a man, anyway. There had been neither head nor arms to the figure, only shapeless masses totally unlike anything human.

They finished packing the breakfast stuff in the supply truck, and the party started out along the trail with Layroh’s sedan leading the way. For nearly two hours they followed their usual routine, working steadily eastward and stopping at regular intervals while Layroh made his methodical tests with his instruments.

Then near the end of the second hour something happened that abruptly sent a thrill of excitement through the entire expedition. Layroh had just set his apparatus up on a small sand dune beside the trail. The mechanism looked somewhat like a portable radio, with two slender parallel rods on top and a number of dials on the main panel.

Layroh swung the rods slowly around the horizon while he carefully tuned the various dials. It was when the rods pointed toward the southeast that there suddenly came the first response he had ever received. From somewhere within the mechanism there came a faint staccato ripple of clear beauty like countless tiny hammers beating upon a crystal gong.

The sound galvanized Layroh into the nearest approach to emotion anyone had ever seen him display. The giant moved with the furious speed of a madman as he returned the apparatus to the sedan and swung the car out across the sand toward the southeast. After a mile he stopped and hurriedly set the apparatus up again. This time the crystalline signal came in with a noticeable increase in volume.

From then on the progress of the party became a mad dash that taxed the endurance of everyone except Layroh himself. After the first hour they entered a terrain so rugged that the cars had to be abandoned and they fought their way forward on foot. Layroh was forced to turn the radiolike apparatus over to one of the men, while he himself carried another mechanism that consisted of a heavy silver cylinder with four flexible nozzles emerging from one end.

They held as rigidly as possible to a straight line toward the southeast, scrambling over whatever obstacles intervened. Their only stops were at regular intervals when Layroh checked their course. Each time the crystalline signal came in with greater volume.

Their objective appeared to be a cone-shaped peak several miles ahead that loomed up high above the surrounding rock masses. The oddly shaped mountain was identified by one of the men who had once been a Mojave desert rat.

“Lodestone Peak,” he announced succinctly. “Full of iron, or somethin’. A compass always goes haywire within a radius of ten miles of it.”

It was early afternoon when they finally arrived at a level area at the base of the mountain. For the last two miles Layroh had not stopped long enough to make any tests. Now he set the radiolike apparatus in place some ten yards from the face of a sheer cliff that towered high above them.

The crystalline signal came in a rippling flood. He spun the dials. The sound ceased, and the pointing rods glowed with an aura of amber light at their tips. Swift and startling answer came from deep within the heart of the cliff, a mighty note of sonorous beauty like the violent plucking of a string on some colossal bass viol. So powerful was the timbre of the pulsing sound that the entire side of the mountain seemed to vibrate in harmony with it.

Layroh snapped off the apparatus and the sound ceased. Carefully searching until he found a certain spot on the cliff face, he stepped close to it and unlimbered the nozzles of the silver cylinder. Foster noted that at the place selected by Layroh there was a five-foot-wide stratum of slightly lighter-colored rock extending from the sand to a point high up on the cliff face.

From the metal nozzles of the cylinder there spurted a broad beam of dead black. There was a searing flash of blue-white flame as the black beam struck the cliff face. There followed a brief second during which the rock melted into nothingness in the heart of that area of blue radiance. Then the stabbing beam bored steadily on back into the cliff like the flame of a blow torch melting a way through a block of butter.

Layroh adjusted the nozzles until the black beam was a solid shaft of opacity seven feet in height and nearly five in width. The hole in the cliff became a tunnel from which blue radiance surged outward in a shimmering mist as the black beam steadily bit deeper into the rock.

“Follow me,” Layroh ordered the men, “but do not approach too close.”

He stepped forward and entered the mouth of the tunnel. Shaken by the spectacular thing occurring before their eyes, yet, driven by curiosity as to what might lie at the end of that swift-forming tunnel, the men came crowding obediently after him. A moment later they were within the passage, stumbling dazedly forward through the billowing fog of bluish radiance. There was an odd, almost electric, tingle of exhilaration in that radiant mist as it surged about their bodies.

Fragments of almost-forgotten scientific lore flitted through Foster’s brain as he groped for a clue to the action of the strange ray. Not quite complete disintegration of matter, but something very close to it--probably the transformation of matter into radiant energy, an ingenious harnessing of the same forces that are forever at work in the cosmic crucibles of the universe’s myriad suns.

The action of the black ray was amazingly rapid. They were forced to hurry forward at a fast walk to keep their distance behind Layroh. The vertical stratum of lighter-colored rock continued straight back into the heart of the mountain. It apparently served as a guide. The color of the blue flame-mist changed perceptibly whenever Layroh allowed the black ray to stray into the rock at either side of it.

For nearly two hundred yards they bored their way steadily into the mountain, their path gradually sloping downward. The walls and floor of the swift-forming tunnel were as smooth and hard as though glazed with a film of diamond.

Then abruptly Layroh shut the black ray projector off as the rock ahead of them ended and they broke through into another larger tunnel, dimly lighted by small globes of violet radiance set at intervals in the glassy ceiling. After thirty yards of travel along this tunnel they found their way barred by a massive door of copper-colored metal.

At Layroh’s imperious gesture the men halted a dozen feet back of him in the tunnel while he brought something out of his leather belt-case. Foster was the only one of the group who was near enough to see that the object was a small tube closely resembling a pocket flashlight.

The only break in the surface of the great door was a six-inch disk over near its right-hand edge. Layroh slid this disk aside. Into the opening that was revealed he sent a series of flashes of colored light from the tube--two red, three green, and two blue. The colors were the combination to the light-activated mechanism of the lock. At the last of the blue flashes there was a whirring of hidden mechanism and the portal swung slowly and ponderously open.

Layroh beckoned to the men to follow him as he strode swiftly on into a vast room that was flooded with bluish light from scores of the radiant globes. As the men passed through the door it reached the limit of its opening swing and began automatically closing again behind them, but they were too completely engrossed in the scene before them to notice it.

They were in a great cavern whose glass-smooth floor was nearly a hundred yards square, and whose ceiling was so high that it was lost in the shadows above the maze of metal girders and cables that made a webwork some forty feet overhead. There was a feeling of almost incredible age about the place, as though it had been sealed away there in the heart of the mountain for countless centuries.

On every hand there was evidence that the cavern and all its contents were the products of a race of beings whose science was one that was utterly strange to that of the modern world. At the end of the room where they stood were row after row of different machines, great engines with bodies of dull silver metal and with stiltlike legs and jointed arms that made them look like giant metal insects. Foster could understand few of the details of the machines, but he felt that in efficiency and versatility they were far ahead of Earth’s best modern efforts.

Grouped together in the center of the cavern were many assemblies of apparatus linked together by small cables that descended from main cables in the girder-crisscrossed ceiling overhead. There was a soft hissing of sparks leaping between terminals and a steady glow from oddly shaped tubes which indicated that the mechanisms were still functioning in silent and efficient performance of their unknown tasks.

The piece of apparatus nearest the door was an upright skeleton framework of slender pillars housing in their center a cluster of coils set around a large drumlike diaphragm. Foster wondered if this were not the signal device with which Layroh had tuned in his own portable instrument. The principal piece of mechanism in the central space, however--a great crystal-walled case filled with an intricate array of rods and wires--was something at whose purpose Foster could not even guess.

Layroh strode on past the central apparatus toward the back wall. The men followed him. Then as they rounded the apparatus and saw for the first time the incredible things lining that rear wall, tier upon tier, they stopped short in utter stupefaction. Before them was Life, but Life so hideously and abysmally alien that their brains reeled in horror.

Great shining slugs slumbered there by the hundreds in their boxlike crystal cells, their gelatinous bodies glowing with pale and ever-changing opalescence. The things were roughly pear-shaped, with the large end upward. Deep within this globular portion glowed a large nucleus spot of red. From the tapering lower part of each slug’s body there sprouted scores of long slender tendrils like the gelatinous fringe of a jelly-fish.

The things measured nearly four feet in height. Each was suspended upright in an individual glass-walled cell, its body supported by a loop of wire that dropped from larger cables running between each row of cells. There was steady and exhaustless power of some kind coursing through those cables. Where they branched at the end of each cell-row there was a small unit of glowing tubes and silver terminals whose tips glowed with faint auras of leaping sparks.

The slugs were dormant now but the regular changes in the opalescent sheen which coursed over their bodies like the slow breathing of a sleeping animal, gave mute evidence that life was still in those grotesque forms, waiting only to be awakened.

Fascinated by the tiers of glowing things, one of the men started slowly forward with a hand outstretched as though to touch one of the cells. His advance aroused Layroh to swift action. The bronze-faced giant whirled and swung the nozzles of the black ray projector into line with the man.

“Back, yaharigan, back!” he ordered imperiously. “The Shining Ones have slumbered, undisturbed for a thousand centuries. They shall not awake from their long sleep to find the filthy fingers of a yaharigan defiling their crystal cells. Back!”

Panic-stricken at the threat of the black ray, the man stumbled backward to join his fellows. Layroh’s startling statement of the incredible age of the shining things in the cases erased all thought of the expedition’s code of rules from Foster’s mind.

“You mean that those--those things--moved and lived in the outside world a hundred thousand years ago?” he asked dazedly. “But there is no indication of there ever having been any such creatures among Earth’s early forms of life.”

“Fool!” There was angry disdain in Layroh’s resonant voice. “They who slumber here are a race born far from this planet. They are the Shining Ones of Rikor. Rikor is a tiny planet circling a wandering sun whose orbit is an ellipse so vast that only once in a hundred thousand years does it approach your solar system. Rikor’s sun was nearly dead and the Shining Ones had to find a new home soon or else perish. Then their planet swung near the Earth, and their scouts returned with the news that Earth was ideally suited for their purpose. There were barely five hundred of the Shining Ones all told, and they migrated to Earth in a body.”

“And they’ve been in this cavern ever since, sealed up like tadpoles in fish bowls?” The question came from Garrigan, a strapping sandy-haired Irishman whose first blind panic at the black ray’s menace was swiftly giving way to curiosity.

“It was your ancestors who drove the Shining Ones into their retreat here,” Layroh answered grimly. “When the Shining Ones arrived upon Earth they found the planet already in the possession of a race of human beings whose science was so far advanced that it compared favorably even with the science of Rikor. This race was comparatively few in numbers, and was concentrated upon a small island-continent known as Atlantis. Shining Ones and Atlanteans met in a war of titans, with a planet as the stake. The Shining Ones were vanquished in that first battle. They lost a fifth of their number and barely half a dozen of their smallest space ships escaped destruction.

“Planning a new and decisive assault, the Shining Ones planted atomic mines throughout the foundations of Atlantis. But the Atlanteans struck first by a matter of hours. At a set moment every volcanic vent on the Earth’s surface belched forth colossal volumes of a green gas. Though that gas was harmless to creatures of Earth, it meant slow but certain death to all Rikorians. Furiously the Shining Ones struck their own blow, setting off the cataclysmic explosion that sank Atlantis forever beneath the waters of the Atlantic. Scarcely a handful of Atlanteans escaped, but Rikor’s victory was a hollow one. Earth’s air was so thoroughly poisoned that it would require centuries of slow ionization by sunlight to again make it fit for Rikorian breathing. The Shining Ones had at most three months before the slow poison would weaken their bodies to the danger point.”

“Why didn’t they go back to their own planet, then, where they belonged?” broke in the truculent voice of Garrigan again.

“That was impossible,” Layroh answered impatiently. “The few space ships they had left would carry barely a score, and Rikor’s sun was already so far advanced in its swing away from Earth that there would be time for only one trip. There was only one chance for survival remaining to them. They knew of a process of suspended animation in which their bodies could survive almost indefinitely without being harmed by the Atlantean gas. They would require outside aid to be awakened from that dormant state, so a small group of them must remain active and embark for Rikor, to try to survive there until Rikor returned near enough to the Earth for them to again cross the void.

“The dormant ones must have a retreat so well hidden that they would not be disturbed during the thousand centuries that must elapse before they could be awakened. The Shining Ones sped back to their base on the North American continent and in the three months remaining to them they prepared this cavern here in the heart of the mountain. Radium bulbs supplied its light. For the unfailing source of electrical energy needed to course through the dormant bodies and keep them alive they tapped the magnetic field of the planet itself, the force produced as the Earth rotates in the sun’s electrical field like an armature spinning within the coils of a dynamo.”

It was Foster who broke in with the question that was in the thoughts of the entire party. “Just where do you come in on all this?” he asked bluntly. “And what was your reason for bringing us here?”

There was blazing contempt in Layroh’s rich voice as he turned toward Foster. “Yaharigan of Earth!” he jeered. “Your brain is as stupid as the feeble brains of those true yaharigans of Rikor whose physical structure your human bodies so closely resemble. Have you not guessed yet that I am no contemptible creature of Earth--that this human shell I wear is nothing but a cleverly contrived disguise? Look, yaharigans, look upon the real face of the one who has come to restore the Earth to its rightful masters!”

With a single swift movement, Layroh snatched the colored goggles from his face and flung them aside. There was a smothered gasp of horror from the group. They saw now why Layroh had always worn those concealing lenses. There were no eyes in that bronzed face, nothing but two empty sockets. And from deep within the skull there glowed through those gaping sockets a seething pool of lurid red--the nucleus spot of a Shining One!

Reeling backward with the rest of the men from the horror of the glowing thing within the skull, Foster dazedly heard Layroh’s resonant voice ring exultantly on: “My ancestors were among the twenty Shining Ones who remained active. After placing their comrades in their long sleep those twenty survivors set up signal apparatus in the cavern so that it could be found again no matter how much the outside terrain might change. Then they filled in the entrance tunnel with synthetic rock and embarked for Rikor.

“There upon that dying planet generations passed. When the time came that Rikor’s sun again neared Earth, so rigorous had life become upon Rikor that only six Rikorians remained alive. In order to increase our chances of winning through on the perilous trip to Earth, each of us traveled in a separate space ship. The precaution was well taken. We encountered a dense cloud of meteors near Alpha Centauri and I was the only survivor.”

Layroh gestured briefly toward the rows of many-armed metal engines. “There are the normal vehicles for a Shining One’s body--armored machines powered by sub-atomic motors and with appendages equipped for every task of peace or war. This synthetic human figure which I now wear was donned only in order that I might have no difficulty in mingling with Earthmen while I sought the cavern. It is an exact replica of the body of an Atlantean, including artificial vocal chords. Even the colored goggles necessary to hide the glowing red of my nucleus are similar to those worn by Atlantean scientists while working with their ray machines--”

Layroh was abruptly interrupted by a scream of maniacal fury from Olsen, a shambling Swede who stood near the edge of the group. Ever since Layroh’s unmasking the Swede had been staring at him with eyes rigidly wide in terror like those of a bird confronting a snake. The steady contemplation of the horror of the blaring red thing behind Layroh’s empty eye-sockets had apparently at last driven the Swede completely insane. He snatched a revolver from his belt as he leaped forward, and fired once. His shot struck Layroh in the forehead.

The bullet ripped through the surface of Layroh’s face, then glanced harmlessly aside as it struck metal underneath. Layroh never even staggered from the impact. The black ray from the projector caught Olsen before he could fire again. There was a searing flash of flame, then a swiftly melting cloud of blue-white radiance, and the Swede was gone.

Layroh swung the projector back to menace the others. “I had forgotten that yaharigans of Earth have weapons that might be annoying,” he said evenly. “Two more of you have pistols--Garrigan and Ransome. Toss them away from you at once. Hesitate--and the black ray speaks again.”

Sullenly the two men obeyed his order.

“Good,” commended Layroh. “In the pits where you are going you will have little use for pistols. When I again take you from those pits you will quickly learn why I brought you with me. Yaharigans, I have called you, and yaharigans you shall be--Earthly counterparts of those miserable beasts of Rikor who have for ages been bred only for the one purpose of supplying food for the Shining Ones. I knew that when I found the cavern the process of awakening the Shining Ones would require that they be carefully fed with the calcium and lime from the bones of living yaharigans, the normal food of all Rikorians.

“The few yaharigans I had brought from Rikor were consumed on my long trip to Earth. So I had to recruit a party of human beings to go with me and serve as the necessary food for the Shining Ones. My search for the cavern took longer than I had expected for I knew only its approximate location. My own body at last had to have sustenance. Last night the Negro, Jeff Peters, provided that sustenance.

“I shall feed those of you who remain to the first group of Shining Ones to be awakened. After that we shall be strong enough in numbers to sally forth and capture ample food for awakening the rest of our comrades. Then in our full strength we shall emerge and again become masters of a planet upon which your crude race shall exist only as yaharigan herds for our sustenance.”

Layroh’s resonant voice ceased. Keeping the black ray projector alertly covering the men, he strode over to a closed metal door in the wall just beyond them. He took a small tube from a rack beside it and opened the door by sending a flash of yellow light into the mechanism of its lock.

“Into the pits until I am ready for you,” he commanded curtly. “They were first constructed for keeping our own yaharigans while we were working in the cavern, and they should serve just as well for you.”

With the memory of Olsen’s tragic fate still fresh in their minds, the men obediently filed into the next room, with Layroh bringing up the rear. The room was little more than a single large cell carved from the living rock, and lighted by a single radium bulb in the ceiling.

Its smooth glasslike floor was broken at intervals of ten feet by circular pits fifteen feet deep. At Layroh’s order the men entered the floor-pits, one man to each pit. As Foster lowered himself into one of them he saw how grimly efficient a trap the pit was.