Only sheer ruthlessness could have taken him out of town Alive. The mob behind Carter hadn't tried to guard the Marsbuggies, since Carter would have needed too much time to take a buggy through the vehicular airlock. They could have caught him there, and they knew it. Some were guarding the personnel lock, hoping he'd try for that. He might have; for if he could have closed the one door in their faces and opened the next, the safeties would have protected him while he went through the third and fourth and outside. On the Marsbuggy he was trapped in the bubble.

There was room to drive around in. Less than half the prefab houses had been erected so far. The rest of the bubbletown's floor was flat fused sand, empty but for scattered piles of foam-plastic walls and ceilings and floors. But they'd get him eventually. Already they were starting up another buggy.

They never expected him to run his vehicle through the bubble wall.

The Marsbuggy tilted, then righted itself. A blast of breathing-air roared out around him, picked up a cloud of fine sand, and hurled it explosively away into the thin, poisoned atmosphere. Carter grinned as he looked behind him. They would die now, all of them. He was the only one wearing a pressure suit. In an hour he could come back and repair the rip in the bubble. He'd have to dream up a fancy story to tell when the next ship came...

Carter frowned. What were they

At least ten wind-harried men were wrestling with the wall of a prefab house. As Carter watched, they picked the wall up off the fused sand, balanced it almost upright, and let go. The foam-plastic wall rose into the wind and slapped hard against the bubble, over the ten-foot rip.

Carter stopped his buggy to see what would happen.

Nobody was dead. The air was not shrieking away but leaking away. Slowly, methodically, a line of men climbed into their suits and filed through the personnel lock to repair the bubble.

A buggy entered the vehicular lock. The third and last was starting to life. Carter turned his buggy and was off.

Top speed for a Marsbuggy is about twenty-five miles per hour. '-The buggy rides on three wide balloon-tired wheels, each mounted at the end of a five-foot arm. What those wheels can't go over, the buggy can generally hop over on the compressed-air jet mounted underneath. The motor and the compressor are both powered by a Litton battery holding a tenth as much energy as the original Hiroshima bomb.

Carter had been careful, as careful as he had had time for. He was carrying a full load of oxygen, twelve four-hour tanks in the air bin behind him, and an extra tank rested against his knees. His batteries were nearly full; he would be out of air long before his power ran low. When the other buggies gave up he could circle round and return to the bubble in the time his extra tank would give him.

His own buggy and the two behind him were the only such vehicles on Mars. At twenty-five miles per hour he fled, and at twenty-five miles per hour they followed. The closest was half a mile behind.

Carter turned on his radio.

He found the middle of a conversation. "-Can't afford it. One of you will have to come back. We could lose two of the buggies, but not all three."

That was Shute, the bubbletown's research director and sole military man. The next voice, deep and sarcastic, belonged to Rufus Doolittle, the biochemist. "What'll we do, flip a coin?"

"Let me go," the third voice said tightly. "I've got a stake in this."

Carter felt apprehension touch the nape of his neck.

"Okay, Alf. Good luck," said Rufus. "Good hunting," he added maliciously, as if he knew Carter were listening.

"You concentrate on getting the bubble fixed. I'll see that Carter doesn't come back."

Behind Carter, the rearmost buggy swung in a wide loop toward

town. The other came on. And it was driven by the linguist, Alf Harness.

Most of the bubble's dozen men were busy repairing the ten-foot rip with heaters and plastic sheeting. It would be a long job but an easy one, for by Shute's orders the bubble had been deflated. The transparent [sic] plastic had fallen in folds across the prefab houses, forming a series of interconnected tents. One could move about underneath with little difficulty.

Lieutenant-Major Michael Shute watched the men at work and decided they had things under control. He walked away like a soldier on parade, stooping as little as possible as he moved beneath the dropping folds.

He stopped and watched Gondot operating the airmaker. Gondot noticed him and spoke without looking up.

"Mayor, why'd you let Alf chase Carter alone?"

Shute accepted his nickname. "We couldn't lose both tractors."

"Why not just post them on guard duty for two days?"

"And what if Carter got through the guard? He must be determined to wreck the dome. He'd catch us with our pants down. Even if some of us got into suits, could we stand another rip in the bubble?"

Gondot reached to scratch his short beard. His fingertips rapped helmet plastic and he looked annoyed. "Maybe not. I can fill the bubble anytime you're ready, but then the airmaker'll be empty. We'll be almost out of tanked air by the time they finish mending that rip. Another'd finish us."

Shute nodded and turned away. All the air anyone could use- tons of nitrogen and oxygen-was right outside; but it was in the form of nitrogen dioxide gas. The -airmaker could convert it three times as fast as men could use it. But if Carter tore the dome again, that would be too slow.

But Carter wouldn't. Alf would see to that. The emergency was over-this time.

And so Lieutenant Major Shute could go back to worrying about the emergency's underlying causes.

His report on those causes had been finished a month ago. He

had reread it several times since, and always it had seemed complete and to the point. Yet he had the feeling it could be written better. He ought to make it as effective as possible. What he had to say could only be said once, and then his career would be over and his voice silenced.

Cousins had sold some fiction once, writing as a hobby. Perhaps he would help. But Shute was reluctant to involve anyone else in what amounted to his own rebellion.

Yet -he'd have to rewrite that report now, or at least add to it. Lew Harness was dead, murdered. John Carter would be dead within two days. All Shute's responsibility. All pertinent.

The decision wasn't urgent. It would be a month before Earth was in reach of the bubbletown's sending station.

Most of the asteroids spend most of their time between Mars and Jupiter, and it often happens that one of them crosses a planet where theretofore it had crossed only an orbit. There are asteroid craters all over Mars. Old eroded ones, sharp new ones, big ones, little ones, ragged and smooth ones. The bubbletown was at the center of a large, fairly recent crater four miles across: an enormous, poorly cast ashtray discarded on the reddish sand.

The buggies ran over cracked glass, avoiding the occasional tilted blocks, running uphill toward the broken rim. A sky the color of blood surrounded a tiny, brilliant sun set precisely at the zenith.

Inevitably Alf was getting closer. When they crossed the rim and started downhill they would pull apart. It was going to be a long chase.

Now was the time for regrets, if there ever was such a time. But Carter wasn't the type, and he had nothing to be ashamed of anyway. Lew Harness had needed to die; had as much as asked to die. Carter was only puzzled that his death should have provoked so violent a reaction. Could they all be-the way Lew had been? Unlikely. If he'd stayed and explained-