“Let’s keep moving,” I told Val. “The surest way to die out here on Mars is to give up.” I reached over and turned up the pressure on her oxymask to make things a little easier for her. Through the glassite of the mask, I could see her face contorted in an agony of fatigue.

And she probably thought the failure of the sandcat was all my fault, too. Val’s usually about the best wife a guy could ask for, but when she wants to be she can be a real flying bother.

It was beyond her to see that some grease monkey back at the Dome was at fault--whoever it was who had failed to fasten down the engine hood.

Nothing but what had stopped us could stop a sandcat: sand in the delicate mechanism of the atomic engine.

But no; she blamed it all on me somehow: So we were out walking on the spongy sand of the Martian desert. We’d been walking a good eight hours.

“Can’t we turn back now, Ron?” Val pleaded. “Maybe there isn’t any uranium in this sector at all. I think we’re crazy to keep on searching out here!”

I started to tell her that the UranCo chief had assured me we’d hit something out this way, but changed my mind. When Val’s tired and overwrought there’s no sense in arguing with her.

I stared ahead at the bleak, desolate wastes of the Martian landscape.

Behind us somewhere was the comfort of the Dome, ahead nothing but the mazes and gullies of this dead world.

[Illustration: He was a cripple in a wheelchair--helpless as a rattlesnake.]

“Try to keep going, Val.” My gloved hand reached out and clumsily enfolded hers. “Come on, kid. Remember--we’re doing this for Earth.

We’re heroes.”

She glared at me. “Heroes, hell!” she muttered. “That’s the way it looked back home, but, out there it doesn’t seem so glorious. And UranCo’s pay is stinking.”

“We didn’t come out here for the pay, Val.”

“I know, I know, but just the same--”

It must have been hell for her. We had wandered fruitlessly over the red sands all day, both of us listening for the clicks of the counter. And the geigers had been obstinately hushed all day, except for their constant undercurrent of meaningless noises.

Even though the Martian gravity was only a fraction of Earth’s, I was starting to tire, and I knew it must have been really rough on Val with her lovely but unrugged legs.

“Heroes,” she said bitterly. “We’re not heroes--we’re suckers! Why did I ever let you volunteer for the Geig Corps and drag me along?”

Which wasn’t anywhere close to the truth. Now I knew she was at the breaking point, because Val didn’t lie unless she was so exhausted she didn’t know what she was doing. She had been just as much inflamed by the idea of coming to Mars to help in the search for uranium as I was.

We knew the pay was poor, but we had felt it a sort of obligation, something we could do as individuals to keep the industries of radioactives-starved Earth going. And we’d always had a roving foot, both of us.

No, we had decided together to come to Mars--the way we decided together on everything. Now she was turning against me.

I tried to jolly her. “Buck up, kid,” I said. I didn’t dare turn up her oxy pressure any higher, but it was obvious she couldn’t keep going. She was almost sleep-walking now.

We pressed on over the barren terrain. The geiger kept up a fairly steady click-pattern, but never broke into that sudden explosive tumult that meant we had found pay-dirt. I started to feel tired myself, terribly tired. I longed to lie down on the soft, spongy Martian sand and bury myself.

I looked at Val. She was dragging along with her eyes half-shut. I felt almost guilty for having dragged her out to Mars, until I recalled that I hadn’t. In fact, she had come up with the idea before I did. I wished there was some way of turning the weary, bedraggled girl at my side back into the Val who had so enthusiastically suggested we join the Geigs.

Twelve steps later, I decided this was about as far as we could go.

I stopped, slipped out of the geiger harness, and lowered myself ponderously to the ground. “What’samatter, Ron?” Val asked sleepily.

“Something wrong?”

“No, baby,” I said, putting out a hand and taking hers. “I think we ought to rest a little before we go any further. It’s been a long, hard day.”

It didn’t take much to persuade her. She slid down beside me, curled up, and in a moment she was fast asleep, sprawled out on the sands.

Poor kid, I thought. Maybe we shouldn’t have come to Mars after all.

But, I reminded myself, someone had to do the job.

A second thought appeared, but I squelched it:

Why the hell me?

I looked down at Valerie’s sleeping form, and thought of our warm, comfortable little home on Earth. It wasn’t much, but people in love don’t need very fancy surroundings.

I watched her, sleeping peacefully, a wayward lock of her soft blonde hair trailing down over one eyebrow, and it seemed hard to believe that we’d exchanged Earth and all it held for us for the raw, untamed struggle that was Mars. But I knew I’d do it again, if I had the chance.

It’s because we wanted to keep what we had. Heroes? Hell, no. We just liked our comforts, and wanted to keep them. Which took a little work.

Time to get moving. But then Val stirred and rolled over in her sleep, and I didn’t have the heart to wake her. I sat there, holding her, staring out over the desert, watching the wind whip the sand up into weird shapes.

The Geig Corps preferred married couples, working in teams. That’s what had finally decided it for us--we were a good team. We had no ties on Earth that couldn’t be broken without much difficulty. So we volunteered.

And here we are. Heroes. The wind blasted a mass of sand into my face, and I felt it tinkle against the oxymask.

I glanced at the suit-chronometer. Getting late. I decided once again to wake Val. But she was tired. And I was tired too, tired from our wearying journey across the empty desert.

I started to shake Val. But I never finished. It would be so nice just to lean back and nuzzle up to her, down in the sand. So nice. I yawned, and stretched back.

I awoke with a sudden startled shiver, and realized angrily I had let myself doze off. “Come on, Val,” I said savagely, and started to rise to my feet.

I couldn’t.

I looked down. I was neatly bound in thin, tough, plastic tangle-cord, swathed from chin to boot-bottoms, my arms imprisoned, my feet caught.

And tangle-cord is about as easy to get out of as a spider’s web is for a trapped fly.

It wasn’t Martians that had done it. There weren’t any Martians, hadn’t been for a million years. It was some Earthman who had bound us.

I rolled my eyes toward Val, and saw that she was similarly trussed in the sticky stuff. The tangle-cord was still fresh, giving off a faint, repugnant odor like that of drying fish. It had been spun on us only a short time ago, I realized.

“Ron--”

“Don’t try to move, baby. This stuff can break your neck if you twist it wrong.” She continued for a moment to struggle futilely, and I had to snap, “Lie still, Val!”

“A very wise statement,” said a brittle, harsh voice from above me. I looked up and saw a helmeted figure above us. He wasn’t wearing the customary skin-tight pliable oxysuits we had. He wore an outmoded, bulky spacesuit and a fishbowl helmet, all but the face area opaque. The oxygen cannisters weren’t attached to his back as expected, though. They were strapped to the back of the wheelchair in which he sat.

Through the fishbowl I could see hard little eyes, a yellowed, parchment-like face, a grim-set jaw. I didn’t recognize him, and this struck me odd. I thought I knew everyone on sparsely-settled Mars.

Somehow I’d missed him.

What shocked me most was that he had no legs. The spacesuit ended neatly at the thighs.

He was holding in his left hand the tanglegun with which he had entrapped us, and a very efficient-looking blaster was in his right.

“I didn’t want to disturb your sleep,” he said coldly. “So I’ve been waiting here for you to wake up.”

I could just see it. He might have been sitting there for hours, complacently waiting to see how we’d wake up. That was when I realized he must be totally insane. I could feel my stomach-muscles tighten, my throat constrict painfully.

Then anger ripped through me, washing away the terror. “What’s going on?” I demanded, staring at the half of a man who confronted us from the wheelchair. “Who are you?”

“You’ll find out soon enough,” he said. “Suppose now you come with me.”

He reached for the tanglegun, flipped the little switch on its side to MELT, and shot a stream of watery fluid over our legs, keeping the blaster trained on us all the while. Our legs were free.

“You may get up now,” he said. “Slowly, without trying to make trouble.”

Val and I helped each other to our feet as best we could, considering our arms were still tightly bound against the sides of our oxysuits.

“Walk,” the stranger said, waving the tanglegun to indicate the direction. “I’ll be right behind you.” He holstered the tanglegun.

I glimpsed the bulk of an outboard atomic rigging behind him, strapped to the back of the wheelchair. He fingered a knob on the arm of the chair and the two exhaust ducts behind the wheel-housings flamed for a moment, and the chair began to roll.

Obediently, we started walking. You don’t argue with a blaster, even if the man pointing it is in a wheelchair.

“What’s going on, Ron?” Val asked in a low voice as we walked. Behind us the wheelchair hissed steadily.

“I don’t quite know, Val. I’ve never seen this guy before, and I thought I knew everyone at the Dome.”

“Quiet up there!” our captor called, and we stopped talking. We trudged along together, with him following behind; I could hear the crunch-crunch of the wheelchair as its wheels chewed into the sand. I wondered where we were going, and why. I wondered why we had ever left Earth.

The answer to that came to me quick enough: we had to. Earth needed radioactives, and the only way to get them was to get out and look. The great atomic wars of the late 20th Century had used up much of the supply, but the amount used to blow up half the great cities of the world hardly compared with the amount we needed to put them back together again.

In three centuries the shattered world had been completely rebuilt. The wreckage of New York and Shanghai and London and all the other ruined cities had been hidden by a shining new world of gleaming towers and flying roadways. We had profited by our grandparents’ mistakes. They had used their atomics to make bombs. We used ours for fuel.

It was an atomic world. Everything: power drills, printing presses, typewriters, can openers, ocean liners, powered by the inexhaustible energy of the dividing atom.

But though the energy is inexhaustible, the supply of nuclei isn’t.

After three centuries of heavy consumption, the supply failed. The mighty machine that was Earth’s industry had started to slow down.

And that started the chain of events that led Val and me to end up as a madman’s prisoners, on Mars. With every source of uranium mined dry on Earth, we had tried other possibilities. All sorts of schemes came forth. Project Sea-Dredge was trying to get uranium from the oceans. In forty or fifty years, they’d get some results, we hoped. But there wasn’t forty or fifty years’ worth of raw stuff to tide us over until then. In a decade or so, our power would be just about gone. I could picture the sort of dog-eat-dog world we’d revert back to. Millions of starving, freezing humans tooth-and-clawing in it in the useless shell of a great atomic civilization.

So, Mars. There’s not much uranium on Mars, and it’s not easy to find or any cinch to mine. But what little is there, helps. It’s a stopgap effort, just to keep things moving until Project Sea-Dredge starts functioning.

Enter the Geig Corps: volunteers out on the face of Mars, combing for its uranium deposits.

And here we are, I thought.

After we walked on a while, a Dome became visible up ahead. It slid up over the crest of a hill, set back between two hummocks on the desert.

Just out of the way enough to escape observation.

For a puzzled moment I thought it was our Dome, the settlement where all of UranCo’s Geig Corps were located, but another look told me that this was actually quite near us and fairly small. A one-man Dome, of all things!

“Welcome to my home,” he said. “The name is Gregory Ledman.” He herded us off to one side of the airlock, uttered a few words keyed to his voice, and motioned us inside when the door slid up. When we were inside he reached up, clumsily holding the blaster, and unscrewed the ancient spacesuit fishbowl.

His face was a bitter, dried-up mask. He was a man who hated.

The place was spartanly furnished. No chairs, no tape-player, no decoration of any sort. Hard bulkhead walls, rivet-studded, glared back at us. He had an automatic chef, a bed, and a writing-desk, and no other furniture.

Suddenly he drew the tanglegun and sprayed our legs again. We toppled heavily to the floor. I looked up angrily.

“I imagine you want to know the whole story,” he said. “The others did, too.”

Valerie looked at me anxiously. Her pretty face was a dead white behind her oxymask. “What others?”

“I never bothered to find out their names,” Ledman said casually. “They were other Geigs I caught unawares, like you, out on the desert. That’s the only sport I have left--Geig-hunting. Look out there.”

He gestured through the translucent skin of the Dome, and I felt sick.

There was a little heap of bones lying there, looking oddly bright against the redness of the sands. They were the dried, parched skeletons of Earthmen. Bits of cloth and plastic, once oxymasks and suits, still clung to them.