Apparently motionless to her passengers and crew, the Interplanetary liner Hyperion bored serenely onward through space at normal acceleration. In the railed-off sanctum in one corner of the control room a bell tinkled, a smothered whirr was heard, and Captain Bradley frowned as he studied the brief message upon the tape of the recorder--a message flashed to his desk from the operator's panel. He beckoned, and the second officer, whose watch it now was, read aloud:

"Reports of scout patrols still negative."

"Still negative." The officer scowled in thought. "They've already searched beyond the widest possible location of the wreckage, too. Two unexplained disappearances inside a month--first the Dione, then the Rhea--and not a plate nor a lifeboat recovered. Looks bad, sir. One might be an accident; two might possibly be a coincidence...." His voice died away. What might that coincidence mean?

"But at three it would get to be a habit," the captain finished the thought. "And whatever happened, happened quick. Neither of them had time to say a word--their location recorders simply went dead. But of course they didn't have our detector screens nor our armament. According to the observatories we're in clear ether, but I wouldn't trust them from Tellus to Luna. You have given the new orders, of course?"

"Yes, sir. Detectors full out, all three courses of defensive screen on the trips, projectors manned, suits on the hooks. Every object detected in the outer space to be investigated immediately--if vessels, they are to be warned to stay beyond extreme range. Anything entering the fourth zone is to be rayed."

"Right--we are going through!"

"But no known type of vessel could have made away with them without detection," the second officer argued. "I wonder if there isn't something in those wild rumors we've been hearing lately?"

"Bah! Of course not!" snorted the captain. "Pirates in ships faster than light--fifth order rays--nullification of gravity--mass without inertia--ridiculous! Proved impossible, over and over again. No, sir, if pirates are operating in space--and it looks very much like it--they won't get far against a good big battery full of kilowatt-hours behind three courses of heavy screen, and a good solid set of multiplex rays. Properly used, they're good enough for anybody. Pirates, Neptunians, angels, or devils--in ships or on sunbeams--if they tackle the Hyperion we'll burn them out of the ether!"

Leaving the captain's desk, the watch officer resumed his tour of duty. The six great lookout plates into which the alert observers peered were blank, their far-flung ultra-sensitive detector screens encountering no obstacle--the ether was empty for thousands upon thousands of kilometers. The signal lamps upon the pilot's panel were dark, its warning bells were silent. A brilliant point of white in the center of the pilot's closely ruled micrometer grating, exactly upon the cross-hairs of his directors, showed that the immense vessel was precisely upon the calculated course, as laid down by the automatic integrating course-plotters. Everything was quiet and in order.

"All's well, sir," he reported briefly to Captain Bradley--but all was not well.

Danger--more serious far in that it was not external--was even then, all unsuspected, gnawing at the great ship's vitals. In a locked and shielded compartment, deep down in the interior of the liner, was the great air purifier. Now a man leaned against the primary duct--the aorta through which flowed the stream of pure air supplying the entire vessel. This man, grotesque in full panoply of space armor, leaned against the duct, and as he leaned a drill bit deeper and deeper into the steel wall of the pipe. Soon it broke through, and the slight rush of air was stopped by the insertion of a tightly fitting rubber tube. The tube terminated in a heavy rubber balloon, which surrounded a frail glass bulb. The man stood tense, one hand holding before his silica-and-steel helmeted head a large pocket chronometer, the other lightly grasping the balloon. A sneering grin was upon his face as he awaited the exact second of action--the carefully pre-determined instant when his right hand, closing, would shatter the fragile flask and force its contents into the primary air stream of the Hyperion!

Far above, in the main saloon, the regular evening dance was in full swing. The ship's orchestra crashed into silence, there was a patter of applause and Clio Marsden, radiant belle of the voyage, led her partner out into the promenade and up to one of the observation plates.

"Oh, we can't see the earth any more!" she exclaimed. "Which way do you turn this, Mr. Costigan?"

"Like this," and Conway Costigan, burly young first officer of the liner, turned the dials. "There--this plate is looking back, or down, at Tellus; this other one is looking ahead."

Earth was a brilliantly shining crescent far beneath the flying vessel. Above her, ruddy Mars and silvery Jupiter blazed in splendor ineffable against a background of utterly indescribable blackness--a background thickly besprinkled with dimensionless points of dazzling brilliance which were the stars.

"Oh, isn't it wonderful!" breathed the girl, awed. "Of course, I suppose that it's old stuff to you, but I--a ground-gripper, you know, and I could look at it forever, I think. That's why I want to come out here after every dance. You know, I ..."

Her voice broke off suddenly, with a queer, rasping catch, as she seized his arm in a frantic clutch and as quickly went limp. He stared at her sharply, and understood instantly the message written in her eyes--eyes now enlarged, staring hard, brilliant, and full of soul-searing terror as she slumped down, helpless but for his support. In the act of exhaling as he was, lungs almost entirely empty, yet he held his breath until he had seized the microphone from his belt and had snapped the lever to "emergency."

"Control room!" he gasped then, and every speaker throughout the great cruiser of the void blared out the warning as he forced his already evacuated lungs to absolute emptiness. "Vee-Two Gas! Get tight!"

Writhing and twisting in his fierce struggle to keep his lungs from gulping in a draft of that noxious atmosphere, and with the unconscious form of the girl draped limply over his left arm, Costigan leaped toward the portal of the nearest lifeboat. Orchestra instruments crashed to the floor and dancing couples fell and sprawled inertly while the tortured First Officer swung the door of the lifeboat open and dashed across the tiny room to the air-valves. Throwing them wide open, he put his mouth to the orifice and let his laboring lungs gasp their eager fill of the cold blast roaring from the tanks. Then, air-hunger partially assuaged, he again held his breath, broke open the emergency locker, donned one of the space-suits always kept there, and opened its valves wide in order to flush out of his uniform any lingering trace of the lethal gas.

He then leaped back to his companion. Shutting off the air, he released a stream of pure oxygen, held her face in it, and made shift to force some of it into her lungs by compressing and releasing her chest against his own body. Soon she drew a spasmodic breath, choking and coughing, and he again changed the gaseous stream to one of pure air, speaking urgently as she showed signs of returning consciousness. Now, it was Clio Marsden's life.

"Stand up!" he snapped. "Hang onto this brace and keep your face in this air-stream until I get a suit around you! Got me?"

She nodded weakly, and, assured that she could now hold herself at the valve, it was the work of only a minute to encase her in one of the protective coverings. Then, as she sat upon a bench, recovering her strength, he flipped on the lifeboat's visiphone projector and shot its invisible beam up into the control room, where he saw space-armored figures furiously busy at the panels.

"Dirty work at the cross-roads!" he blazed to his captain, man to man--formality disregarded, as it so often was in the Triplanetary service. "There's skulduggery afoot somewhere in our primary air! Maybe that's the way they got those other two ships--pirates! Might have been a timed bomb--don't see how anybody could have stowed away down there through the inspections, and nobody but Franklin can neutralize the shield of the air-room--but I'm going to look around, anyway. Then I'll join you fellows up there."

"What was it?" the shaken girl asked. "I think that I remember your saying 'Vee-Two gas.' That's forbidden! Anyway, I owe you my life, Conway, and I'll never forget it--never. Thanks--but the others--how about all the rest of us?"

"It was Vee-Two, and it is forbidden," Costigan replied grimly, eyes fast upon the flashing plate, whose point of projection was now deep in the bowels of the vessel. "The penalty for using it or having it is death on sight. Gangsters and pirates use it, since they have nothing to lose, being on the death list already. As for your life, I haven't saved it yet--you may wish I'd let it ride before we get done. The others are too far gone for oxygen--couldn't have brought even you around a few seconds later, quick as I got to you. But there's a sure antidote--we all carry it in a lock-box in our armor--and we all know how to use it, because crooks all use Vee-Two and so we're always expecting it. But since the air will be pure again in half an hour we'll be able to revive the others easily enough if we can get by with whatever is going to happen next. There's the bird that did it, right in the air-room! It's the chief engineer's suit, but that isn't Franklin that's in it. Some passenger--disguised--slugged the chief--took his suit and projectors--hole in duct--p-s-s-t! All washed out! Maybe that's all he was scheduled to do to us in this performance, but he'll do nothing else in this life!"

"Don't go down there!" protested the girl. "His armor is so much better than that emergency suit you are wearing, and he's got Mr. Franklin's Lewiston, besides!"

"Don't be an idiot!" he snapped. "We can't have a live pirate aboard--we're going to be altogether too busy with outsiders directly. Don't worry, I'm not going to give him a break. I'm taking a Standish and I'll rub him out like a blot. Stay right here until I come back after you," he commanded, and the heavy, vacuum insulated door of the lifeboat clanged shut behind him as he leaped out into the promenade.

Straight across the saloon he made his way, paying no attention to the inert forms scattered here and there. Going up to a blank wall, he manipulated an almost invisible dial set flush with its surface, swung a heavy door aside, and lifted out the Standish--a fearsome weapon. Squat, huge, and heavy, it resembled somewhat an overgrown machine rifle, but one possessing a thick, short telescope, with several opaque condensing lenses and parabolic reflectors. Laboring under the weight of the thing, he strode along corridors and clambered heavily down short stairways. Finally he came to the purifier room, and grinned savagely as he saw the greenish haze of light obscuring the door and walls--the shield was still in place; the pirate was still inside, still flooding with the terrible Vee-Two the Hyperion's primary air.

He set his peculiar weapon down, unfolded its three massive legs, crouched down behind it and threw in a switch. Dull red beams of frightful intensity shot from the reflectors and sparks, almost of lightning proportions, leaped from the shielding screen under their impact. Roaring and snapping, the conflict went on for seconds; then, under the superior force of the Standish, the greenish radiance gave way. Behind it the metal of the door ran the gamut of color--red, yellow, blinding whiter--then literally exploded; molten, vaporized, burned away. Through the aperture thus made Costigan could plainly see the pirate in the space-armor of the chief engineer--an armor which was proof against rifle fire and which could reflect and neutralize for some little time even the terrific beam Costigan was employing. Nor was the pirate unarmed--a vicious flare of incandescence leaped from his Lewiston, to spend its force in spitting, crackling pyrotechnics against the ether-wall of the squat and monstrous Standish. But Costigan's infernal machine did not rely only upon vibratory destruction. At almost the first flash of the pirate's weapon the officer touched a trigger; there was a double report, ear-shattering in that narrowly confined space; and the pirate's body literally flew into mist as a half-kilogram shell tore through his armor and exploded. Costigan shut off his beam, and, with not the slightest softening of one hard lineament, stared around the air-room; making sure that no serious damage had been done to the vital machinery of the air-purifier--the very lungs of the great space-ship.

Dismounting the Standish, he lugged it back up to the main saloon, replaced it in its safe and again set the combination lock. Thence to the lifeboat, where Clio cried out in relief as she saw that he was unhurt.

"Oh, Conway, I've been so afraid something would happen to you!" she exclaimed, as he led her rapidly upward toward the control room. "Of course you...." she paused.

"Sure," he replied, laconically. "Nothing to it. How do you feel--about back to normal?"

"All right, I think, except for being scared to death and just about out of control. I don't suppose that I'll be good for anything, but whatever I can do, count me in on."

"Fine--you may be needed, at that. Everybody's out, apparently, except those who, like me, had a warning and could hold their breath until they got to their suits."

"But how did you know what it was? You can't see it, nor smell it, nor anything."

"You inhaled a second before I did, and I saw your eyes. I've been in it before--and when you see a man get a jolt of that stuff just once, you never forget it. The engineers down below got it first, of course--it must have wiped them out. Then we got it in the saloon. Your passing out warned me, and luckily I had enough breath left to give the word. Quite a few of the fellows up above should have had time to get away--we'll see 'em all in the control room."

"I suppose that was why you revived me--in payment for so kindly warning you of the gas attack?" The girl laughed; shaky, but game.

"Something like that, probably," he answered, lightly. "Here we are--now we'll soon find out what's going to happen next."

In the control room they saw at least a dozen armored figures; not now rushing about, but seated at their instruments, tense and ready. Fortunate it was that Costigan--veteran of space as he was, though young in years--had been down in the saloon; fortunate that he had been familiar with that horrible outlawed gas; fortunate that he had had the presence of mind enough and sheer physical stamina enough to send his warning without allowing one paralyzing trace to enter his own lungs. Captain Bradley, the men on watch, and several other officers in their quarters or in the wardrooms--space-hardened veterans all--had obeyed instantly and without question the amplifiers' gasped command to "get tight." Exhaling or inhaling, their air-passages had snapped as that dread "Vee-Two" was heard, and they had literally jumped into their armored suits of space--flushing them out with volume after volume of unquestionable air; holding their breath to the last possible second, until their straining lungs could endure no more.

Costigan waved the girl to a vacant bench, cautiously changed into his own armor from the emergency suit he had been wearing, and approached the captain.

"Anything in sight, sir?" he asked, saluting. "They should have started something before this."

"They've started, but we can't locate them. We tried to send out a general sector alarm, but that had hardly started when they blanketed our wave. Look at that!"

Following the captain's eyes, Costigan stared at the high powered set of the ship's operator. Upon the plate, instead of a moving, living, three-dimensional picture, there was a flashing glare of blinding white light; from the speaker, instead of intelligible speech, was issuing a roaring, crackling stream of noise.

"It's impossible!" Bradley burst out, violently. "There's not a gram of metal inside the fourth zone--within a hundred thousand kilometers--and yet they must be close to send such a wave as that. But the Second thinks not--what do you think, Costigan?" The bluff commander, reactionary and of the old school as was his breed, was furious--baffled, raging inwardly to come to grips with the invisible and undetectable foe. Face to face with the inexplicable, however, he listened to the younger men with unusual tolerance.

"It's not only possible; it's quite evident that they've got something we haven't." Costigan's voice was bitter. "But why shouldn't they have? Service ships never get anything until it's been experimented with for years, but pirates and such always get the new stuff as soon as it's discovered. The only good thing I can see is that we got part of a message away, and the scouts can trace that interference out there. But the pirates know that, too--it won't be long now," he concluded, grimly.

He spoke truly. Before another word was spoken the outer screen flared white under a beam of terrific power, and simultaneously there appeared upon one of the lookout plates a vivid picture of the pirate vessel--a huge, black globe of steel, now emitting flaring offensive beams of force. Her invisibility lost, now that she had gone into action, she lay revealed in the middle of the first zone--at point-blank range.

Instantly the powerful weapons of the Hyperion were brought to bear, and in the blast of full-driven beams the stranger's screens flamed incandescent. Heavy guns, under the recoil of whose fierce salvos, the frame of the giant globe trembled and shuddered, shot out their tons of high-explosive shell. But the pirate commander had known accurately the strength of the liner, and knew that her armament was impotent against the forces at his command. His screens were invulnerable, the giant shells were exploded harmlessly in mid-space, miles from their objective. And suddenly a frightened pencil of flame stabbed brilliantly from the black hulk of the enemy. Through the empty ether it tore, through the mighty defensive screens, through the tough metal of the outer and inner walls. Every ether-defence of the Hyperion vanished, and her acceleration dropped to a quarter of its normal value.

"Right through the battery room!" Bradley groaned. "We're on the emergency drive now. Our rays are done for, and we can't seem to put a shell anywhere near her with our guns!"

But ineffective as the guns were, they were silenced forever as a frightful beam of destruction stabbed relentlessly through the control room, whiffing out of existence the pilot, gunnery, and lookout panels and the men before them. The air rushed into space, and the suits of the three survivors bulged out into drumhead tightness as the pressure in the room decreased.

Costigan pushed the captain lightly toward a wall, then seized the girl and leaped in the same direction.

"Let's get out of here, quick!" he cried, the miniature radio instruments of the helmets automatically taking up the duty of transmitting speech as the sound disks refused to function. "They can't see us--our ether wall is still up and their spy-sprays can't get through it from the outside, you know. They're working from blue-prints, and they'll probably take your desk next," and even as they bounded toward the door, now become the outer seal of an airlock, the annihilating ray tore through the space which they had just quitted in their flight.

Through the airlock, down through several levels of passengers' quarters they hurried, and into a lifeboat, whose one doorway commanded the full length of the third lounge--an ideal spot, either for defense or for escape outward by means of the miniature cruiser. As they entered their retreat they felt their weight begin to increase. More and more force was applied to the helpless liner, until it was moving at normal acceleration.

"What do you make of that, Costigan?" asked the captain. "Tractor beams?"

"Apparently. They've got something, all right. They're taking us somewhere, fast. I'll go get a couple of Standishes, and another suit of armor--we'd better dig in," and soon the small room became a veritable fortress, housing as it did, those two formidable engines of destruction. Then the first officer made another and longer trip, returning with a complete suit of triplanetary space armor, exactly like those worn by the two men, but considerably smaller.

"Just as an added factor of safety, you'd better put this on, Clio--those emergency suits aren't good for much in a battle. I don't suppose that you ever fired a Standish, did you?"

"No, but I can soon learn how to do it," she replied, pluckily.

"Two is all that can work here at once, but you should know how to take hold in case one of us goes out. And while you're changing suits you'd better put on some stuff I've got here--Service special phones and detectors. Stick this little disk onto your chest with this bit of tape; low down, out of sight. Just under your wishbone is the best place. Take off your wrist-watch and wear this one continuously--never take it off for a second. Put on these pearls, and wear them all the time, too. Take this capsule and hide it against your skin, some place where it can't be found except by the most rigid search. Swallow it in an emergency--it goes down easily and works just as well inside as outside. It is the most important thing of all--you can get along with it alone if you lose everything else, but without that capsule the whole system's shot to pieces. With that outfit, if we should get separated, you can talk to us--we're both wearing 'em, although somewhat different forms. You don't need to talk loud--just a mutter will be enough. They're handy little outfits, almost impossible to find, and capable of a lot of things."

"Thanks, Conway--I'll remember that, too," Clio replied, as she turned toward the tiny locker to follow his instructions. "But won't the scouts and patrols be catching us pretty quick? The operator sent a warning."

"Afraid the ether's empty, as far as we're concerned. They could neutralize our detector screens, and the scouts' detectors are the same as ours."

Captain Bradley had stood by in silent astonishment during this conversation. His eyes had bulged slightly at Costigan's "we're both wearing 'em," but he had held his peace and as the girl disappeared a look of dawning comprehension came over his face.

"Oh, I see, sir," he said, respectfully--far more respectfully than he had ever before addressed a mere first officer. "Meaning that we both will be wearing them shortly, I assume. 'Service Specials'--but you didn't specify exactly what Service, did you?"

"Now that you mention it, I don't believe that I did," Costigan grinned.

"That explains several things about you--particularly your recognition of Vee-Two and your uncanny control and speed of reaction. But aren't you...."

"No," Costigan interrupted, positively. "This situation is apt to get altogether too serious to overlook any bets. If we get away, I'll take them away from her and she'll never know that they aren't routine equipment in the Triplanetary Service. As for you, I know that you can and do keep your mouth shut. That's why I'm hanging this junk on you--I had a lot of stuff in my kit, but I flashed it all with the Standish, except what I brought in here for us three. Whether you think so or not, we're in a real jam--our chance of getting away is mightly close to zero. Now that I've gone this far, I might as well tell you that I don't believe these birds are pirates at all, in the ordinary sense of the word. And it may be possible that they're after me, but I don't think so--we've covered up too...."

He broke off as the girl came back, now to all appearances a small Triplanetary officer, and the three settled down to a long and eventless wait. Hour after hour they flew through the ether, but finally there was a lurching swing and an abrupt increase in their acceleration. After a short consultation Captain Bradley turned on the visiray set and, with the beam at its minimum power, peered cautiously downward, in the direction opposite to that in which he knew the pirate vessel must be. All three stared into the plate, seeing only an infinity of emptiness, marked only by the infinitely remote and coldly brilliant stars. While they stared into space a vast area of the heavens was blotted out and they saw, faintly illuminated by a peculiar blue luminescence, a vast ball--a sphere so large and so close that they seemed to be dropping downward toward it as though it were a world! They came to a stop--paused, weightless--a vast door slid smoothly aside--they were drawn upward through an airlock and floated quietly in the air above a small, but brightly-lighted and orderly city of metallic buildings! Gently the Hyperion was lowered, to come to rest in the embracing arms of a regulation landing cradle.

"Well, wherever it is, we're here," remarked Captain Bradley, grimly.

"And now the fireworks start," assented Costigan, with a questioning glance at the girl.

"Don't mind me," she answered his unspoken question. "I don't believe in surrendering, either."

"Right," and both men squatted down behind the ether-walls of their terrific weapons; the girl prone behind them.

They had not long to wait. A group of human beings--men and to all appearance Americans--appeared unarmed in the little lounge. As soon as they were well inside the room, Bradley and Costigan released upon them without compunction the full power of their frightful projectors. From the reflectors, through the doorway, there tore a concentrated double beam of pure destruction--but that beam did not reach its goal. Yards from the men it met a screen of impenetrable density. Instantly the gunners pressed their triggers and a stream of high-explosive shells issued from the roaring weapons. But shells, also, were futile. They struck the shield and vanished--vanished without exploding and without leaving a trace to show that they had ever existed.

Costigan sprang to his feet, but before he could launch his intended attack a vast tunnel appeared beside him--an annihilating ray had swept through the entire width of the liner, cutting instantly a smooth cylinder of emptiness. Air rushed in to fill the vacuum, and the three visitors felt themselves seized by invisible forces and drawn into the tunnel. Through it they floated, up to and over the buildings, finally slanting downward toward the door of a great high-powered structure. Doors opened before them and closed behind them, until at last they stood upright in a room which was evidently the office of a busy executive. They faced a desk which, in addition to the usual equipment of the business man, carried a bewilderingly complete switchboard and instrument panel.

Seated impassively at the desk there was a gray man. Not only was he dressed entirely in gray, but his heavy hair was gray, his eyes were gray, and even his tanned skin seemed to give the impression of grayness in disguise. His overwhelming personality radiated an aura of grayness--not the gentle gray of the dove, but the resistless, driving gray of the super-dreadnaught; the hard, inflexible, brittle gray of the fracture of high-carbon steel.

"Captain Bradley, First Officer Costigan, Miss Marsden," the man spoke quietly, but crisply. "I had not intended you two men to live so long. That is a detail, however, which we will pass by for the moment. You may remove your suits."

Neither officer moved, but both stared back at the speaker unflinchingly.

"I am not accustomed to repeating instructions," the man at the desk continued; voice still low and level, but instinct with deadly menace. "You may choose between removing those suits and dying in them, here and now."

Costigan moved over to Clio and slowly took off her armor. Then, after a flashing exchange of glances and a muttered word, the two officers threw off their suits simultaneously and fired at the same instant; Bradley with his Lewiston, Costigan with a heavy automatic pistol whose bullets were explosive shells of tremendous power. But the man in gray, surrounded by an impenetrable wall of force, only smiled at the fusillade, tolerantly and maddeningly. Costigan leaped fiercely, only to be hurled backward as he struck that unyielding, invisible wall. A vicious beam snapped him back into place, the weapons were snatched away, and all three captives were held in their former positions.

"I permitted that, as a demonstration of futility," the gray man said, his hard voice becoming harder, "but I will permit no more foolishness. Now I will introduce myself. I am known as Roger. You probably have heard nothing of me yet but you will--if you live. Whether or not you two live depends solely upon yourselves. Being something of a student of men, I fear that you will both die shortly. Able and resourceful as you have just shown yourselves to be, you could be valuable to me, but you probably will not--in which case you shall, of course, cease to exist. That, however, in its proper time--you shall be of some slight service to me in the process of being eliminated. In your case, Miss Marsden, I find myself undecided between two courses of action; each highly desirable, but unfortunately mutually exclusive. Your father will be glad to ransom you at an exceedingly high figure, but, in spite of that fact, I may decide to keep you for--well, let us say for certain purposes."

"Yes?" Clio rose magnificently to the occasion. Fear forgotten, her courageous spirit flashed from her clear, young eyes and emanated from her slender, rounded young body, erect in defiance. "Since I am a captive, you can of course do anything you please with me up to a certain point--but no further, believe me!"

With no sign of having heard her outburst Roger pressed a button and a tall, comely woman, appeared--a woman of indefinite age and of uncertain nationality.

"Show Miss Marsden to her apartment," he directed, and as the two women went out a man came in.

"The cargo is unloaded, sir," the newcomer reported. "The two men and the five women indicated have been taken to the hospital," was the report of the man.

"Very well, dispose of the others in the usual fashion." The minion went out, and Roger continued, emotionlessly:

"Collectively, the other passengers may be worth a million or so, but it would not be worth while to waste time upon them."

"What are you, anyway?" blazed Costigan, helpless but enraged beyond caution. "I have heard of mad scientists who tried to destroy the earth, and of equally mad geniuses who thought themselves Napoleons capable of conquering even the Solar System. Whichever you are, you should know that you can't get away with it."

"I am neither. I am, however, a scientist, and I direct many other scientists. I am not mad. You have undoubtedly noticed several peculiar features of this place?"

"Yes, particularly the artificial gravity, which has always been considered impossible, and those screens. An ordinary ether-wall is opaque in one direction, and doesn't bar matter--yours are transparent both ways and something more than impenetrable to matter. How do you do it?"

"You could not understand them if I explained them to you, and they are merely two of our smaller developments. I have no serious designs upon the earth nor upon the Solar System, nor have I any desire to rule over, or to control the destinies of masses of futile and brainless men. I have, however, certain ends of my own in view. To accomplish my plans I require hundreds of millions in gold, other hundreds of millions in platinum and noble metal, and some five kilograms of the bromide of radium--all of which I shall take from the planets of this Solar System before I leave it. I shall take them in spite of the puerile efforts of the fleets of your Triplanetary League.

"This structure, floating in a planetary orbit, was designed by me and built under my direction. It is protected from meteorites by certain forces of my devising. It is undetectable and invisible--your detectors do not touch it and light-waves are bent around it without loss or distortion. I am discussing these points at such length so that you may realize exactly your position. As I have intimated, you can be of assistance to me if you will."

"Now just what could you offer any man to make him join your outfit?" demanded Costigan, venomously.

"Many things." Roger's cold tone betrayed no emotion, no recognition of Costigan's open and bitter contempt. "I have under me many men, bound to me by many ties. Needs, wants, longings and desires differ from man to man, and I can satisfy practically any of them. Personally, I take delight in the society of young and beautiful women, and many men have that same taste; but there are other urges which I have found quite efficient. Greed, thirst for fame, longing for power, and so on, including many qualities usually regarded as 'noble.' And what I promise, I deliver. I demand only loyalty to me, and that only in certain things and for a relatively short period. In all else, my men do as they please. In conclusion, I can use you two conveniently, but I do not need you. Therefore you may choose now between my service and--the alternative."

"Exactly what is the alternative?"

"We will not go into that. Suffice it to say that it has to do with a minor research, which is not progressing satisfactorily. It will result in your extinction, and perhaps I should mention that that extinction will not be particularly pleasant."

"I say NO, you...." Bradley roared. He intended to give an unexpurgated classification, but was rudely interrupted.

"Hold on a minute!" snapped Costigan. "How about Miss Marsden?"

"She has nothing to do with this discussion," returned Roger, icily. "I do not bargain--in fact, I believe that I shall keep her for a time. She has it in mind to destroy herself, if I do not allow her to be ransomed, but she will find that door closed to her until I permit it to open."

"In that case, I string along with the Chief--take what he started to say about you and run it clear across the board for me!" barked Costigan.

"Very well. That decision was to be expected from men of your type." The gray man touched two buttons and two of his creatures entered the room. "Put these men into separate cells on the second level," he ordered. "Search them to the skin: all their weapons may not have been in their armor. Seal the doors and mount special guards, tuned to me here."

Imprisoned they were, and carefully searched; but they bore no arms, and nothing had been said or thought of communicators. Even if such instruments could be concealed, Roger would detect their use instantly. At least, so would have run his thought had the subject entered his mind. But even Roger had no inkling of the possibility of Costigan's "Service Special" phones, detectors and spy-ray--instruments of minute size and of infinitesimal power, but yet instruments which, working as they were, below the level of the ether, were effective at great distances and caused no vibrations in the ether by which their use could be detected. And what could be more innocent than the regulation, personal equipment of every officer of space? The heavy goggles, the wrist-watch and its supplementary pocket chronometer, the flash-lamp, the automatic lighter, the sender, the money-belt?

All these items of equipment were examined with due care; but the cleverest minds of Triplanetary's Secret Service had designated those communicators to pass any ordinary search, however careful, and when Costigan and Bradley were finally locked into the designated cells, they still possessed their ultra-instruments.