The Comet's control-room was silent except for the monotonous beat of Ken Grant's restless pacing. Six months on Ceres' frigid, shadowy Darkside had driven the tan from his face, etched lines of worry about his mouth. Darkside had a way of doing that to people. A temperature of five above absolute zero, the grim, eternal darkness, the insane landscape, combined to give an impression of unreality that made one feel he was living some terrible nightmare.

From time to time Grant glanced at the sidereal chronometer, shook his head. Sixteen hours! Sixteen hours since Kennerly had left ... and the heating unit of his space-suit had been good for three! Kennerly had vanished, just as Allers had vanished before him! Two men had left the disabled ship to try and reach Bowman's Crater, that last tiny outpost only twenty miles away, and both men had disappeared. Had either Allers or Kennerly been successful, a rescue ship from Bowman's Crater must have come by now. But instead, the two spacemen had been swallowed up by the gloom, vanished, leaving no trace. The bitter silent darkness outside was like some yawning limitless void into which men went, and did not return. Their position was bad enough in any case, but with a woman in command....

Grant shot a glance at the stack of big lead chests in a corner of the cabin. Pitchblend—radium ore with an amazingly high metal content. The ore in those big chests, when refined, would yield over a million in the rare element. Not that a million would do them much good if they couldn't get it away. With the main fuel intake valve cracked, the motors, the radio, the air-regenerator, were all shut off. Death from lack of oxygen faced them unless word got through.

A click of the cabin's door broke Grant's thoughts. He turned; a slender girl wearing riding breeches and leather jacket appeared in the doorway. Pale, with deep smoke-gray eyes and auburn hair, she had a fragile transcendental beauty that was very appealing, but her chin was firm, determined.

"Any news, Mr. Grant?" she asked quietly, stepping into the control room.

"None." He shook a gloomy head. "I don't like it! There's something strange going on, Miss Conway! The trail's perfectly clear, there's no life on Ceres that we know of. One man might conceivably meet with some sort of accident, but not two! They tell stories about Darkside; queer stories! About alien, unknown creatures."

"I ... I know," the girl said tightly. "Dad used to hear those stories, too, when he and Allers were prospecting here. When Dad died he left me enough money to charter this ship, told me to come here to Ceres for my legacy. Gave me the chart showing where this pocket of pitchblend was located." She glanced at the lead chests. "Now Allers, Dad's closest friend, is gone. And Kennerly. And we're trapped, made virtual prisoners in this ship by something unknown—out there. We've got to get word through, Mr. Grant! It's death to stay here until our oxygen is gone. Death, maybe worse, waiting for us out there in the darkness...." She broke off, suddenly, swaying.

"Steady!" Grant gripped the girl's shoulder. "It's the bad air! I'll go tell Harris to crack open one of the emergency oxygen flasks. You'd better lie down."

Like a flash the girl's red head snapped up. "You're a romanticist, Mr. Grant," she said. "You seem to think I ought to be a languishing heroine. Well, I'm not. I'm in command of this expedition and if there're any risks to be taken, I'm taking them! Have Harris open an oxygen flask and then check over my space-suit! As soon as I get my breath, I'm going out and look for Allers and Kennerly!" She waved aside Grant's remonstrances. "Orders, Mr. Grant!"

Face stony, Grant left the control room, strode along the companionway to the fo'castle. The Comet's crew, perhaps half a dozen men all told, were stretched upon their bunks, faces drawn as they fought against the stale air. Grant motioned to Harris, the squat, ugly mate.

"Air's getting thick," he said. "Better crack an emergency tube."

"Aye, aye, sir!" Harris lifted a steel plate in the floor, swung down the iron ladder. Some moments later he emerged from the storehold, carrying an oxygen flask.

"Funny!" The mate rubbed his stubbly chin. "I coulda swore we had twenty emergency flasks below. But there's only five more down there."

"Five!" Grant's eyes narrowed. "There were twenty when we left earth! I counted 'em!"

"That's not all," Harris muttered. "There's other stores missing! Wire, tools, batteries, spare plates for repairing the hull!" His eyes flicked toward the darkness beyond the portholes. "There were plenty of times we were all down at the mine working when whatever it was that got Allers and Kennerly might have entered the ship, taken those things. I've seen shadows out there sometimes. Shadows that weren't just right, sliding among the rocks. And ... and it's bad luck to have a woman aboard ship."

A silence fell over the cabin. Grant frowned. Five flasks of oxygen ... and the air-regenerator useless without power! Nothing could save them unless word got through to Bowman's Crater, on the edge of the Cerean Darkside. Two men had tried to get through, and those two men had vanished. To permit Joan Conway to attempt the trip was unthinkable. Grant reached for one of the bulky space-suits that hung on the wall.

"All right, men," he grated. "We're going to get to the bottom of this! Here's the plan! I'll take the trail to Bowman's Crater; the same trail Allers and Kennerly took! If there's anything lying in wait out there, it ought to attack me, and I'll be armed! At the same time I want you, Harris, and you, Miller, to go out also, to climb the other side of the crater and circle about, picking up the trail to Bowman's a mile or so from here. I'll draw It's attention, while you try to get through and take word to the outpost. Got it?"

The three men nodded, climbed into the heavily insulated space-suits. Electric heating wires ran through the lining, from portable batteries good for several hours, enabling the men within them to maintain comfortable warmth even though the soles of their thick lead gravity shoes, in contact with the icy ground, were within a few degrees of absolute zero. Gloves of heavy lead, a part of every radium miner's equipment as protection against the highly concentrated ore he was forced to handle, covered the asbestoid "hands" of the space-suits. Grant paused before snapping his transparent plastic helmet into place, turned to the men who were to remain aboard the Comet.

"Miss Conway's feeling a little ragged because of the air," he said, unsmilingly. "When she's better, tell her where we've gone."

The men grinned understandingly. They knew that the girl, in spite of her frail form, felt that command of the expedition required her to share in all its dangers. And Grant, like most men who had spent their lives on far-flung frontiers, seeking adventure in the woman-less outposts of terrestial civilization, had curiously archaic ideas of chivalry, to say nothing of deep-rooted convictions that a woman's place was on earth. Disregarding the grins of the men, he closed his helmet, opened the valve of his oxygen tank.

"Ready?" he barked into the mouthpiece of his radio communications set.

Two space-suited figures nodded grimly behind their helmets, followed Grant through the airlock. In the clean, airless void the stars shone like white beacons, shedding a thin eerie light over the barren plain. A dark inferno worthy of a Dore's brush, it seemed, malevolent, intangibly evil. Tortured pinnacles of rock, jagged spires stabbing at the sable sky; deep craters, dug by countless meteors, pock-marking the bleak terrain; yawning crevasses, towering cliffs, jagged, sharp-angled blocks of stone, for Darkside had neither sun, air, nor rain to round them, soften their weird outlines.

Grant loosened his heat-gun in its holster, glanced about. Up the side of the big crater, in which the mine-shaft and the space-ship lay, was a poorly defined trail, winding in and out among the towering rocks. This was the way to Bowman's, the little mining town situated in the twilight zone between Ceres' bitter Darkside and its blazing Sunside. Allers and Kennerly had taken that rude trail. Grant waved Harris and Miller to the right.

"You'll make a long half-circle," he announced. "It'll be tough going, but with my following the trail, I should draw any attack and enable you to pick up the trail further along, and reach Bowman's. Okay, now. Let's go!"

Harris and Miller disappeared among the up-thrust monoliths, Grant swung along the trail. In spite of his heavy space-suit and his thick lead-soled gravity shoes, he was able to move at a brisk pace, hand on his gun, eyes probing the gloom to right and left. Onward he went, steadily, skirting craters, leaping narrow crevasses, squeezing through rocky defiles whose overhanging ledges often met to form a dark passageway. For all the heating wires within his suit, he could feel the cold; the utter silence was maddening.

Grant stared at the murky shadows with narrowed eyes. What was it that had spirited away Allers and Kennerly, two brave men, well armed? Some unknown force of nature, or something more tangible? Superstitious spacemen whispered of monstrous reptilian beasts, of space-pirates' hide-outs, of strange, spectral Shapes. Drink-inspired hallucinations, Grant had said scornfully. Now he was not so sure. So little was known of Darkside.

Suddenly Grant froze in his tracks. In the middle of the path, perhaps a hundred feet ahead, was a strange, grotesque figure. Swathed in a bulky space-suit, it crouched ape-like on the ground, feet flat against the rock, hands touching the trail as though to balance itself. Motionless as some robot it crouched there, in a patch of white frost, seemingly poised to spring.

Grant's heat-gun rose to cover the strange figure. His voice shook as he spoke into his communications set.

"Who's there? What'd you want?"

The crouching figure made no reply. Very deliberately Grant pressed the trigger of the heat-gun, aiming it at the motionless form's feet. Dirt, chips of stone, flew up, but the crouching form did not move. Muscles tense, Grant moved forward. Pale starlight winked on the unknown's helmet. All at once Grant gasped. Behind the transparent glass of the headpiece, the man's features were visible. Distorted, despairing features set in an expression of ghastly, appalling horror! Kennerly ... dead!

Grant bent over the grim figure, tried to lift it. One of Kennerly's fingers, frozen solid, snapped within the space-suit like brittle glass. Grant glanced warily about. If he could get the body back to the ship, find out how Kennerly had died, there might be a chance of overcoming the menace that lurked on this shadowy insane world. All at once his eyes caught queer dark streaks on a rock not far from the inert figure ... letters, words, that looked as if they had been made by a heat-gun's blast. Slowly he deciphered the scrawled sentences. "Allers dead. No hope. Unknown forces. Doomed."

Grant's jaw tightened. Kennerly's last message! And somehow he had known that Allers was dead, that there was no hope. Face set in harsh lines, Grant swung the body over his shoulder, set out along the trail to the Comet.

The silence in the space-ship's control-room was thick, breathless. A frail figure against the rivet-studded bulkhead, Joan Conway stared with horror-filled eyes at the grim figure on the floor. They had removed Kennerly's space-suit, and with the warmth of the cabin the stump of the frozen finger which Grant had inadvertently broken off was beginning to seep blood. The girl forced her voice to remain steady.

"Under the circumstances, Mr. Grant," she said tightly, "I have decided to overlook your disobedience of orders until we return to earth ... if we do. Are there any clues on Kennerly?"

Grant, kneeling beside the dead man, examining him carefully, shook his head.

"Nothing," he muttered. "No holes in his suit, no signs of anything that might have killed him other than the cold. The battery of his heating unit's run down. And he had a full charge when he left. We checked it. Why he should follow the trail a mile or so from the ship and then sit there for hours, until the failing battery brought death by freezing.... It's suicide!"

"Maybe he got lost, wandered around until he died," one of the space-hands suggested.

"No good." Again Grant shook a somber head. "The trail's perfectly clear. I found him in a deep patch of hoar frost, like snow. Condensed moisture from the escape valve of his helmet. An extraordinarily large patch of 'snow.' Get what that means? Frost patches in this airless void can only mean the moisture from a space-suit's exhaust. And a pile of 'snow' like that about him, could only be the result of remaining hours in one spot. Kennerly left this ship for Bowman's Crater, got about two miles away and then crouched down to wait for death. Crouched there for hours, until his heating unit ran out of juice and he froze. Why?" Grant motioned to the inert form' with its terrified countenance. "He had sustained no injury, could have followed a perfectly clear path back to the ship, and instead he crouched there until he died!"

"Maybe something held him," Joan suggested. "Magnetism."

Grant picked up the asbestoid space-suit. "Fiber, glassex helmet, rust-proof copper fittings, lead gravity shoes. No iron or steel on it. Another thing. How did he know Allers was dead? What did he mean by 'unknown forces' and 'no hope?' There's something devilish, unreal, out there. Something that's determined to keep us from getting word through, determined to keep us here until we die from lack of oxygen! Just like Kennerly died from lack of heat. It's afraid to attack us, but tries to trap us, until we die."

Again silence fell over the cabin. The remaining space-hands glanced from Kennerly's body to the windows, the clinging darkness outside. Joan's gaze sought the leaden chests; she laughed unhumorously.

"Pitchblend! A million in radium! And what good is it? All our work here to get it and now no chance of ever reaching earth."

"We'll get word through somehow." Grant squared his shoulders. "Maybe Harris and Miller...."

As Grant spoke, a furious tocsin of blows sounded upon the main airlock. The spacemen whirled, groping for guns. Face set, Grant stepped toward the inner door of the lock.

"Keep me covered," he snapped, drawing the massive pneumatic bolts.

As the heavy steel door swung open, Joan gave a sudden gasp. Standing in the air-chamber was a stocky, space-suited figure, face paper-white. Harris, looking as though he were pursued by a legion of devils!

"Good Lord!" Grant exclaimed. "What's wrong? Where's Miller?"

Harris pushed back his helmet, slumped onto a bench; drops of sweat beaded his face, his eyes were tortured.

"It ... it's screwy!" he muttered. "It ain't human! Miller standing there, jumping up and down."

Grant took a bottle of fiery Martian long from the table, poured out a tumblerful.

"Drink this," he said. "And tell us what happened."

Harris downed the drink with a shudder.

"We made the detour like you said," he whispered. "Fighting our way over rocks, around craters. Tough going. About three miles from here our half-circle brought us back to the trail. All okay. Miller was ahead of me by maybe a hundred yards. We kept our guns in our hands, and a sharp lookout. Then ... then ... all of a sudden I heard Miller yelling in my earphones. He was hopping up and down ... straight up and down, half-crazy with fright.... Just as I was running toward him, he told me to stay back, that he was trapped. Trapped!" Harris choked. "He could hop up and down all right, but he couldn't move in the horizontal! Nothing around him, nothing to be seen anywhere, but he could only move one way! Up and down! It ain't human, I tell you! Ain't natural! How...."

"Miller could move only in the vertical?" Joan echoed. "But ... but ... no comprehensible force on earth...."

"This ain't earth, miss," Harris muttered. "And Miller's out there, three miles up the trail, trapped...."

Grant reached for his space-suit. "Come on!" he exclaimed. "We're going out! Harris, you'll stay here with Miss Conway...."

"No!" The girl shook her head, eyes like gray steel. "I'm in command of this expedition ... and I'm going along! Danger or no danger! I got you men into this mess, and I'm going to help you get out!"

"Sorry." Grant shook his head. "I admire your courage, but we're up against something unknown, something dangerous. You'd be more of a hindrance than a help. Call me old-fashioned, romantic, anything you please, but you're staying here. Harris, I'll be responsible for any charges of insubordination. See that she stays here. We're going to rescue Miller."

Lips pale, head high, the girl watched them clamber into their space-suits. Her pride, Grant realized, was cut deeply at having the command of the expedition thus taken from her. But this was no time for pride with Miller trapped by some mysterious force. Motioning to the others to follow, Grant sprang into the airlock.

Leaving the ship, the six men raced at top speed along the trail. Around crevasses and craters, past insanely sculptured rocks, through narrow passes. When they reached the spot where Kennerly's body had been found, Grant suddenly paused, staring. The patch of hoar-frost had been scraped away, a small hole perhaps a foot deep was exposed. Something previously buried in the ground had been removed! Grant shook his head. A bizarre, fantastic idea was beginning to take form in his mind. In a temperature close to absolute zero....

"Come on!" he exclaimed. "We've got to reach Miller! Hurry!"

The spacemen redoubled their efforts, bounding along the narrow path. Onward, desperately, the sound of their heavy breathing filling their helmets. At length they reached a low rise of ground commanding a view of the trail ahead. Very faintly a despairing cry echoed in their earphones.

A hundred or so yards before them, a vague form in the gloom, stood Miller. His head twisted crazily from side to side, his body writhed frantically, as if seeking to break some invisible grip. Several times he leaped upward like some grotesque jumping-jack, only to settle down in the exact same spot as before. It was as though the trapped man were confined in an invisible cylinder which permitted him to move only in the vertical plane!

"Look!" Grant muttered. "So it's true! That's what happened to Kennerly until his heating unit gave out! And Allers, too, I suppose!" He raced down the slope toward Miller, heat-gun in hand.

As they neared the trapped man, he gave a cry of warning. "Stay back! You'll get caught!" His voice rose despairingly. "No ... no way to get free! Hands and feet stuck! Better to shoot me, now, than let me stay here till my heat-unit gives out!"

Helplessly they stared at the doomed man. To approach him meant they, too, might be trapped. But to stand there, useless, while his heating unit gave out, bringing death, as it had brought death to Kennerly! And what power known to man would permit a living being to move only in the vertical plane but not the horizontal? All at once Grant recalled the hole in the trail at the spot where he had found Kennerly. Dropping to his knees, he began very cautiously to circle Miller. All at once he found it, a copper wire concealed beneath dirt, pebbles. One jerk of his gloved fingers snapped the wire. A sudden cry broke from the trapped man. Weakly, uncertainly, he stepped forward.

"Free!" Miller cried. "I ... I can move my feet and hands any way I want, now! Thank God! The thought of staying there until I froze to death...!" He shuddered.

Grant was following the wire to where Miller had stood, was digging away a covering of earth. All at once he gave an exclamation of wonder. In the wan starlight a tangle of wires, wrapped about iron cores, lay exposed!

"Looks like a magnet!" A burly space-hand grunted, shaking a dazed head. "But there's no iron on our suits! And no magnet permits you to move only one way!"

"I don't know." Grant frowned. "But whatever this force is, it's got a clever, devilish mind behind it! This is the same kind of thing that trapped Kennerly, only we didn't reach him in time. When I first spotted Kennerly crouching in the trail, I didn't know who he was. Fired a warning shot at his feet. That must have fused the wires of the apparatus! And so I was able to approach Kennerly's body without being trapped myself! While I was taking his body back to the ship, the killer must have dug up the wrecked mechanism, planted this magnet further down the trail! If Harris hadn't been lagging a considerable distance behind Miller, they both would have been caught!"

"Sounds logical," one of the men nodded. "But why all these traps? And who's setting them?"

Grant picked up the broken end of the wire.

"That," he said grimly, "is what we're going to find out. At the other end of this wire is the source of power for these traps. And that's where we'll find the person or being who's setting them! Let's go!"

The spacemen nodded, faces tense behind their helmets. Leaving the trail, they struck out across the rough terrain, following the thin thread of wire. The scenery grew wilder and wilder as they progressed, until they seemed spectres in some gehenna of weird, jagged rocks, grasping shadows. Suddenly Grant, in the lead, drew a sharp breath.

Ahead, the copper wire passed between two basalt walls, less than four feet wide. And at the other end of this passage was a portable radite lamp, its bluish beams revealing a small motor, a row of tall oxygen flasks, wires, metal plates, the missing equipment from the Comet's storehold. And bent over the motors was a powerful space-suited figure!

"Quick!" Grant roared. "We've got him!" Fingers fumbling for his heat-gun, he sprang forward.

Grant's leap, in the light gravity, carried him clear of the ground, and at that precise instant the dark figure before him threw a switch. A sudden shock hit Grant; he felt as if his hands and feet had been lashed by invisible bonds. He glanced down, gasped. He was standing on empty air, some two feet above the rocky floor of the corridor!

Behind him, the rest of the spacemen were frozen into position, writhing and twisting in vain efforts to free themselves! Grant struggled to draw his gun from its holster, but his hands, while free to move sideways, could not be raised or lowered a fraction of an inch. As Kennerly and Miller had been trapped in the vertical, so they were caught in the horizontal!

"Good evening, gentlemen!" The voice in their earphones was mocking. "I've been expecting you! I hoped that the wire would lead you here, into my little snare!" The space-suited figure glanced at the struggling men. "All present except Harris and the girl! And they'll open the airlock to admit an old friend miraculously returned from the dead!"

Grant, catching a glimpse of the face behind the unknown's helmet, gave a quick gasp.

"Allers!" he cried. "Then ... then Kennerly's message was a lie."

"I wrote it myself." A grin spread over Allers' coarse red countenance. "Just to keep suspicion from me. You see, Grant, I was with old Conway when he stumbled on the pitchblend pocket, and I knew the fortune it contained. But when Conway died, I didn't have enough money to finance an expedition here. So as soon as I heard his daughter was going to outfit a ship on his life insurance, I joined up." He laughed harshly. "You've been such fools! Night after night, during these six months, I've been bringing necessary equipment from the ship to this hide-out. Oxygen, food, metal, this little auxiliary motor, and fuel to run it. When you had done all the work of cleaning out the pocket, I cracked the main intake valve, volunteered to get word through to Bowman's Crater. And while you were waiting, I set my traps along the trail."

Allers nodded complacently, drew a small, complicated piece of machinery from his pocket.

"Here's the spare intake valve," he said. "Harris and the girl will be overjoyed to see dear old Allers return. They won't be suspecting anything and should be easy." He patted the heat gun at his side. "The ship and the million in radium ore will be mine with no trouble at all. And there're places on Venus or Mars where no questions are asked, so long as you've the money to spend."

"But what's holding us here?" Grant exclaimed.

Allers smiled thinly. "Think it over," he suggested. "You'll have three hours before your heating units give out, as Kennerly's did. And even if you do find out the cause, you won't be able to do anything about it." He strode easily past the helpless figures, unaffected by the mysterious force. "Good-bye, gentlemen! Enjoy yourselves!" A moment later he had disappeared in the gloom.

Left to themselves, the trapped men renewed their struggles, but to no avail. Grant felt as though his feet and hands were caught between two boards, able to slide sideways but neither forward and backward, nor up and down. He glanced over his shoulder. The others were in ridiculous positions, like some bizarre Laocoon group. Some, like him, had leaped clear of the floor when caught. Others had one foot or one hand raised, were unable to lower them; some, with their guns half-drawn, could not continue to pull the weapons from their holsters or shove them back. Miller, hands and feet arrested in a flying tackle, groaned.

"This is worse than before," he muttered. "I could at least jump up and down the other way. Now, without being able to lift our feet, we're rooted to one spot. And my heating unit's two hours gone already."

Grant stared at the frantic man. Like some queer piece of action sculpture they seemed, arms and legs raised. And back aboard the Comet Joan and Harris would surely admit Allers. Once inside, he could cover them with his gun, replace the broken valve, and take off for Venus.

"We'll have to go at this logically," he said. "We just saw Allers walk past us without being affected. Anybody notice anything unusual about him?"

There was a moment's silence, then one of the space-hands spoke up.

"He didn't have on gravity shoes or radium-insulation gloves, if that means anything."

"They're both lead," Grant muttered. "And ... by all space! I think I've got it! Look! The temperature here is only a couple of degrees above absolute zero. And though the inside of our suits are warmed, insulated, the soles of our shoes, the outside of our thick lead gloves, must be near that temperature! Lead, at six above absolute zero, takes on super-conductivity. No resistance to electricity! Weak currents become immensely powerful!"

"Super-conductivity?" Miller repeated. "But what in hell's that got to do with our being caught here? We've got to get free, and damn soon, before our heating units give out!"

"Look," Grant snapped. "He's got magnets set in the walls of this gorge! And when the lead on our hands and feet, in a state of super-conductivity, cuts the fields of the magnets, a powerful current's set up in 'em! Set up in such a direction as to oppose the motion! Like the armature of a shorted dynamo! Get it? We can move only in the direction of the lines of force! Sideways! Just like the magnet that caught you, buried beneath your feet, kept you in the vertical plane! Super-conductivity, and magnets! That's what's got us!"

"Knowing what it is doesn't help," Miller grated. "We can't get our heat-guns free, and even if we could, we wouldn't dare turn them on our hands and feet! Looks like we're here to stay until our heating units wear down and we freeze! We're finished, Grant! Finished!"

Grant swore. His hands and feet, inside the space-suit, were warm, but the outer lead gloves that were a part of every radium miner's equipment, and the thick lead soles of their gravity shoes, were at approximately six above absolute zero. A degree, or even half a degree, of warmth, and super-conductivity would cease. They would be free! Their lives, and Joan Conway's fate, depended upon those few precious degrees. Desperately Grant tried to pull his heat-gun from its holster, but to no avail. And the leaden gloves, the gravity shoes, were securely fastened to his space-suit. No chance of removing them without cutting wires or filing bolts.

Grant moved his hands experimentally. They slid sideways, following the lines of magnetic force that crossed the passage, though at different levels; one on a level with the butt of his gun, the other higher and extended in front of his body. Backward and forward motion was also impossible, since that, too, would be contrary to the lines of force. Suddenly Grant stiffened. Arrested motion....

Extending his arm as far as possible without raising it, he crashed his hand against the holstered heat gun that hung at his waist. Again and again the lead-sheathed fist struck the heavy holster in a rain of blows. Miller, watching wide-eyed, shook his head.

"What is it?" he muttered. "You ... you're nuts! If that gun should go off, it'd rip open your suit, kill you!"

"Better than freezing, anyhow," Grant panted. "And if this works...." He redoubled his blows, crashing hand against gun-butt. "Arrested motion gives heat. Like pounding a hammer against an anvil. Only need a degree or so at most. I ... Ah!" He twisted his hand about, found that he could move it freely.

Quickly, before the heat radiated off, Grant drew his heat-gun, focused it on the floor of the defile. Under the lambent blue bolt, the rock began to glow red, waves of heat radiated upward. All at once Grant found himself falling, and his feet struck the glowing rock. The lead soles of his shoes melting like butter on the white-hot rock, he stumbled toward Miller, turned the heat blast on a spot near the latter's feet. Within a few moments the heat had restored resistance to the lead and Miller was free.

"Release the others!" Grant shouted. "And then make tracks to the Comet! I'm going on ahead! Hurry! We've got to reach the ship before Allers takes off for Venus!" Plunging into the shadowy gloom, he headed toward the trail.

Ken Grant had little memory of that wild race across the Cerean Darkside. The thin starlight ... the insane landscape ... the sprawling shadows ... all these made a jumbled montage in his mind. Vaguely he remembered racing onward, onward, muscles aching, until he saw red flashes of light ahead. The Comet's rockets, warming up preparatory to taking off!

Desperately Grant lunged down the slope toward the ship. Now it was before him, a sleek, slender shape, glowing in the crimson flare of the rockets. Grant gripped the handle of the airlock, sunk flush in the hull, and tugged. The outer door swung open. Closing it behind him, he threw open the inner one and burst into the cabin, gun in hand. Before him stood Joan, very pale, chin high. Harris lay upon the floor, blood seeping from a gash on his temple. All this Grant took in with one swift glance, but before he could move he felt the muzzle of a gun dig into his back. Allers, standing to one side of the airlock as he entered, held him covered.

"Drop your gun!" Allers shouted to make himself heard through Grant's helmet.

Helpless, Grant obeyed, then threw back the transparent plastic dome that covered his head.

"Over there against the wall! Next to the girl!" Allers ordered. "I don't know how you got free, but I'm not staying to investigate! We're leaving for Venus!" He moved toward the controls, bent over them, keeping Grant and Joan covered with his heat gun. Grant laughed harshly. A nice mess he'd made of things!

One of Allers' hands was on the main control, the other gripped the heat gun. An idea began to take form in Grant's mind. The cold, the bitter cold just above absolute zero, was what Allers had counted on to trap them. Perhaps it might save them as well. He hadn't been in the cabin long enough for the cold to wear off. Grant drew a deep breath.

"Shoot, damn you!" he roared, hurtling forward.

Face set in a vulpine grin, Allers pressed the trigger of the heat-gun. Joan's horrified scream ripped through the cabin like a jagged knife blade.

"Ken!" she cried. "Ken!"

The ray of the heat-gun was like a white hot lance, thrusting against Grant's chest as he plunged toward Allers. In spite of the space-suit's insulation it would normally have charred him to a crisp, but the suit, bitterly cold from the fierce temperature of Darkside, sucked up the heat like a sponge. Grant felt as though a glowing brand had touched his chest, the pain was terrible, but the frigid cold of the suit absorbed the full force of the heat blast long enough for him to reach his opponent.

One blow of Grant's lead-gloved fist caught Allers' face, spun him about. The heat-gun flew from his hand, slithered under the big control board. Bruised, bloody, snarling in savage rage, Allers shook himself, hurtled forward, fists flailing.

Grant, encased in the heavy space-suit, was clumsy, awkward. Allers circled him like a tiger stalking its prey. Darting in, his fist would crash into his opponent's face before Grant could raise his heavy arms to guard. And by the time he was ready for a return blow, Allers was dancing out of reach, a grinning, ugly phantom.

Doggedly, Grant pursued his elusive antagonist. His face was a battered pulp from Allers' blows and the space-suit, the gravity shoes seemed to weigh tons. Except for that first blow he had not reached his opponent once, and Allers was laughing mockingly as he methodically cut Grant's face to ribbons. The latter was beginning to stumble now, had to force his limbs to move. If only he could corner Allers! Smash his fist into that evil, taunting countenance.

Knotted knuckles crashed flush against Grant's jaw, before he could raise his clumsy arm to block the blow. Backward he tottered against the wall, groggy, and through half-closed eyes saw Allers spring forward for the kill. But as Allers leaped toward him, another figure ran across the cabin, seized his arm. Joan! Clinging with all her weight to the space-rat, holding him back.

"Now, Ken!" she cried. "Now!"

With a single motion of his squat, powerful frame Allers shook the girl off, spun her across the cabin against the iron bulkhead, but in that moment Grant had reached him. His lead-encased hands shot out, gripped Allers' throat. The cold of the leaden gloves burned the man's neck like a brand and he screamed in agony. Tighter and tighter Grant's hands locked about his throat, heedless of the blows Allers rained upon him, and the agonized scream turned into a gurgling moan.

"Think of Kennerly!" Grant growled. "Dying out there in the cold! Think of him, you rat!"

Then a million stars danced before Grant's eyes, and he slumped back, half-conscious. Through wavering mists he saw Allers stagger to his feet, gripping a heavy wrench. The space-rat's groping hands had encountered it, brought the weapon down upon his opponent's head with brutal force. It was all like a dream, now, to Grant. Stunned, helpless, he saw Allers moving toward him, face set in a furious grin, the heavy wrench raised for a final terrible blow.

Instinctively Grant twisted sideways, his fingers fumbled with the emergency outlet of his space-suit's oxygen tank. On his shoulders it had escaped the heat-ray's blast and Grant knew it was still full of semi-liquid oxygen, under heavy pressure.

Allers' muscles were tensing, the heavy wrench was about to descend in a crushing, deadly stroke. It took all of Grant's failing strength to twist the outlet of the air valve.

The cloud of whitish vapor spurted from the space-suit's outlet in an icy stream. For just an instant Allers stood motionless as the blast of semi-liquid oxygen struck him. A howl of agony broke from his lips, the wrench fell from his half-frozen fingers. Then, crimsoned features strangely set, body rigid, Allers toppled to the floor.

"Ken!" Joan whispered. "Ken, you ... you're all right?"

"O ... okay!" His gaze lingered on her piquant features, with their firm, level eyes, brave set of chin. "You know," he said slowly, "I believe that crack on the head knocked me silly. So silly that for a moment I actually believed you wouldn't mind if I ki...." He paused as Miller and the rest of the crew pounded excitedly on the massive outer door of the airlock.

"Let them wait," Joan Conway said peremptorily, "and finish what you were saying!" Then, as he hesitated, "Orders, Mr. Grant!"

"Aye, aye, Commander," Grant grinned. "I was going to say I believed you wouldn't mind if I kissed you. Like this!"