"Fistfight my aunt's purple asterisk. You hit Lew in the throat and watched him drown in his own blood. Don't tell me you didn't know what you were doing. Everybody in town knows you know karate."

"He died in minutes. I'll need a whole day!"

"You don't like that? Turn around and rush my gun It's right here waiting."

"We could get back to the crater in time to search for that Martian. That's why I came to Mars. To learn what's here. So did you, Alf. Come on, let's turn back."

"You first."

But he couldn't. He couldn't. Karate can defeat any hand-to-hand weapon but a quaterstaff, and Carter had quarterstaff training too. But he couldn't charge a flare gun!

Not even if Alf meant to turn back. And Alf didn't.

A faint whine vibrated through the bubble. The sandstorm was at the height of its fury, which made it about as dangerous as an enraged caterpillar. At worst it was an annoyance. The shrill barely audible whine could get on ones nerves, and the darkness made streetlamps necessary. Tomorrow the bubble would be covered a tenth of an inch deep in fine, Moon-dry silt. Inside the bubble it would be darker than night until someone blew the silt away with an 0-tank.

To Shute the storm was depressing. Here on Mars was Lieutenant-Major Shute, Boy Hero, facing terrifying dangers on the frontiers of human exploration! A sandstorm that wouldn't have harmed an infant. n.o.body here faced a single danger that he had not brought with him.

Would it be like this forever? Men traveling enormous distances to face themselves?

There had been little work done since noon today. Shute had given up on that. On a stack of walls sat Timmy, practically surrounding the buggy-pickup radio, surrounded in turn by the bubble's population.

Timmy stood up as Shute approached the group. "They're gone," he announced, sounding very tired. He turned off the radio. The men looked at each other, and some got to their feet.

"Tim! How'd you lose them?"

Timmy noticed him.

"They're too far away, Mayor."

"They never turned around?"

"They never did. They just kept going out into the desert. Alf must have gone insane.

Carter's not worth dying for."

Shute thought, But he was once. Carter had been one of the best: tough, fearless, bright, enthusiastic. Shute had watched him deteriorate under the boredom and the close quarters aboard ship. He had seemed to recover when they reached Mars, when all of them suddenly had work to do. Then, yesterday mourning--murder.

Alf. It was hard to lose Alf. Lew had been little loss, but Alf-- Cousins dropped into step beside him.

"I've got that red-pencil work done."

"Thanks, Lee. I'll have to do it all over now."

"Don't do it over. Write an addendum. Show how and why three men died. Then you can say, 'I told y so.' "

"You think so?"

"My professional judgment. When's the funeral?"

"Day after tomorrow. That's Sunday. I thought it would be appropriate."

"You can say all three services at once. Good timing."

To all bubbletown, Jack Carter and Alf Harness were dead. But they still breathed-- The mountains came toward them: the only fixed points in an ocean of sand. Alf was closer now, something less than four hundred yards behind. At five o'clock Carter reached the base of the mountains.

They were too high to go over on the air jet. He could see spots where he might have landed the buggy while the pump filled the jet tank for another hop. But for what?

Better to wait for Alf.

Suddenly Carter knew that that was the one thing in the world Alf wanted. To roll up alongside in his buggy. To watch Carter's face until he was sure Carter knew exactly what was to come. And then to blast Carter down in flames from ten feet away, and watch while a bright magnesium-oxidizer flare burned through his suit and skin and vitals.

The hills were low and shallow. Even from yards away he might have been looking at the smooth flank of a sleeping beast--except that this beast was not breathing. Carter took a deep breath, noticing how stale the air had become despite the purifier unit, and turned on the compressed-air jet.

The air of Mars is terribly thin, but it can be compressed; and a rocket will work anywhere, even a compressed-air rocket. Carter went up, leaning as far back in the cabin as he could to compensate for the loss of weight in the 0-tanks behind him, to put as little work as possible on gyroscopes meant to spin only in emergencies. He rose fast, and he tilted the buggy to send it skating along the thirty-degree slope of the hill. There were flat places along the slope, but not many. He should reach the first one easily...

A flare exploded in his eyes. Carter clenched his teeth and fought the urge to look behind. He tilted the buggy backward to slow him down. The jet pressure was dropping.

He came down like a feather two hundred feet above the desert. When he turned off the jet he could hear the gyros whining. He turned the stabilizer off and let them run down.

Now there was only the chugging of the compressor, vibrating through his suit.

Alf was out of his buggy, standing at the base of the mountains, looking up.

"Come on," said Carter.

"What are you waiting for?"

"Go on over if you want to."

"What's the matter? Are your gyros fouled?"

"Your brain is fouled, Carter. Go on over." Alf raised one arm stiffly out. The hand showed flame, and Carter ducked instinctively.

The compressor had almost stopped, which meant the tank was nearly full. But Carter would be a fool to take off before it was completely full. You got the greatest acceleration from an air jet during the first seconds of flight. The rest of the flight you got just enough pressure to keep you going.

But--Alf was getting into his buggy. Now the buggy was rising.

Carter turned on his jet and went up.

He came down hard, three hundred feet high, and only then dared to look down. He heard Alf's nasty laugh, and he saw that Alf was still at the foot of the mountains. It had been a bluff!

But why wasn't Alf coming after him?

The third hop took him to the top. The first downhill hop was the first he'd ever made, and it almost killed him. He had to do his decelerating on the last remnants of pressure in the jet tank! He waited until his hands stopped shaking, then continued the rest of the way on the wheels. There was no sign of Alf as he reached the foot of the range and started out into the desert.

Already the sun was about to go. Faint bluish stars in a red-black sky outlined the yellow hills behind him.

Still no sign of Alf.

Alf spoke in his ear, gently, almost kindly.

"You'll just have to come back, Jack."

"Don't hold your breath."

"I'd rather not have to. That's why I'm telling you this. Look at your watch."

It was about six-thirty.

"Did you look? Now count it up. I started with fortyfour hours of air. You started with fifty-two. That gave us ninety-six breathing hours between us. Together we've used up sixty-one hours. That leaves thirty-five between us.

"Now, I stopped moving an hour ago. From where I am it's almost thirty hours back to base. Sometime in the next two and a half hours, you've got to get my air and stop me from breathing. Or I've got to do the same for you."

It made sense. Finally, everything made sense.

"Alf, are you listening? Listen," said Carter, and he opened his radio panel and, moving by touch, found a wire he'd located long ago. He jerked it loose. His radio crackled deafeningly, then stopped.

"Did you hear that, Alf? I just jerked my come-hither loose. Now you couldn't find me even if you wanted to."

"I wouldn't have it any other way."

Then Carter realized what he'd done. There was now no possibility of Alf finding him.

After all the miles and hours of the chase, now it was Carter chasing Alf. All Alf had to do was wait.

The dark fell on the west like a heavy curtain.

Carter went south, and he went immediately. It would take him an hour or more to cross the range. He would have to leapfrog to the top with only his headlights to guide him.

His motor would not take him uphill over such a slope. He could use the wheels going down, with luck, but he would have to do so in total darkness. Deimos would not have risen; Phobos was not bright enough to help.

It had gone exactly as Alf had planned. Chase Carter to the range. If he attacks there, take his tanks and go home. If he makes it, show him why he has to come back. Time it so he has to come back in darkness. If by some miracle he makes it this time--well, there's always the flare gun.

Carter could give him only one surprise. He would cross six miles south of where he was expected, and approach Alf's buggy from the southeast.

Or was Alf expecting that too?

It didn't matter. Carter was beyond free will.

The first jump was like jumping blindfolded from a ship's airlock. He'd pointed the headlights straight down, and as he went up he watched the circle of light expand and dim. He angled east. First he wasn't moving at all. Then the slope slid toward him, far too fast. He back-angled. Nothing seemed to happen. The pressure under him died slowly, but it was dying, and the slope was a wavering blur surrounded by dark.

It came up, clarifying fast.

The landing jarred him from coccyx to cranium. He held himself rigid, waiting for the buggy to tumble end- for-end down the hill. But though the buggy was tilted at a horrifying angle, it stayed.

Carter sagged and buried his helmet in his arms. Two enormous hanging tears, swollen to pinb.a.l.l.s in the low gravity, dropped onto his faceplate and spread. For the first time he regretted all of it. Killing Lew, when a kick to the kneecap would have put him out of action and taught him a permanent, memorable lesson. s.n.a.t.c.hing the buggy instead of surrendering himself for trial. Driving through the bubble--and making every man on Mars his mortal enemy. Hanging around to watch what would happen--when, perhaps, he could have run beyond the horizon before Alf came out the vehicular airlock. He clenched his fists and pressed them against his faceplate, remembering his att.i.tude of mild interest as he sat watching Alf's buggy roll into the lock.

Time to go. Carter readied himself for another jump. This one would be horrible. He'd be taking off with the buggy canted thirty degrees backward...

Wait a minute.

There was something wrong with that picture of Alf's buggy as it rolled toward the lock surrounded by trotting men. Definitely something wrong there. But what?

It would come to him. He gripped the jet throttle and readied his other hand to flip on the gyros the moment he was airborne.

--Alf had planned so carefully. How had he come away with one 0-tank too few?

And--if he really had everything planned, how did Alf expect to get Carter's tanks if Carter crashed?

Suppose Carter crashed his buggy against a hill, right now, on his second jump. How would Alf know? He wouldn't, not until nine o'clock came and Carter hadn't shown up.

Then he'd know Carter had crashed somewhere. But it would be too late!

Unless Alf had lied.

That was it, that was what was wrong with his picture of Alf in the vehicular airlock.

Put one 0-tank in the air bin and it would stand out like a sore thumb. Fill the air bin and then remove one tank, and the hole in the hexagonal array would show like Sammy Davis Jr on the Berlin n.a.z.i's football team! There had been no such hole.

Let Carter crash now, and Alf would know it with four hours in which to search for his buggy.

Carter swung his headlights up to normal position, then moved the buggy backward in a dead-slow half circle. The buggy swayed but didn't topple. Now he could move down behind his headlights...

Nine o'clock. If Carter was wrong then he was dead now. Even now Alf might be unfastening his helmet, his eyes blank with the ultimate despair, still wondering where Carter had got to. But if he was right...

Then Alf was nodding to himself, not smiling, merely confirming a guess. Now he was deciding whether to wait another five minutes on the chance that Carter was late, or to start searching now. Carter sat in his dark cabin at the foot of the black mountains, his left hand clutching a wrench, his eyes riveted on the luminous needle of the direction finder.

The wrench had been the heaviest in his toolbox. He'd found nothing sharper than a screwdriver, and that wouldn't have penetrated suit fabric.

The needle pointed straight toward Alf.

And it wasn't moving.

Alf had decided to wait.

How long would he wait?

Carter caught himself whispering, not loudly. Move, idiot. You've got to search both sides of the range. Both sides and the top. Move. Move!

Ye G.o.ds! Had he shut off his radio? Yes, the switch was down.

Move.

The needle moved. It jerked once, infinitesimally, and was quiet.

It was quiet a long time--seven or eight minutes. Then it jerked in the opposite direction.