Space was dependent only upon three coordinates. When one dictated a set of space coordinates one shifted space itself. Any energy or mass contained in that space thereupon shifted with that space shift.

In the matter of a motor such as this freighter had, it was just an enclosed housing in which space coordinates could be changed. As the coordinates changed, the housing was forced to go along, and this gave the motor power.

That explained why these planes were run by a switchboard and not a thrust through the air. They didn't have to have wings or controls. Much smaller housings in the tail and on each side had similar sets of coordinates fed into them to climb and bank. A series of coordinates were progressively fed to the main motor and it simply went forward or backward as the housed space occupied each set of coordinates in turn.

Teleportation over vast distances worked the same way. Matter and energy were pinned to the space, and when it was exchanged with another space, they simply changed too. Thus matter and energy would seem to disappear in one place and appear in another. They didn't actually change. Only the space did.

Jonnie could see now how Earth had been attacked. Informed in some way of its existence, possibly from some

Psychlo station in this universe, the Psychlos had only to fish in its coordinates.

They evidently used a recorder of some sort. They cast the recorder out to a test set of coordinates and then got it back and looked at the pictures. If the recorder vanished they knew they had sent it into the mass of the planet. Then they just had to adjust the coordinates for a new recorder cast.

In that way they had sent the killer gas. When it dissipated, they had followed it with Psychlos and weapons.

That was how Earth had been wiped out and conquered. But it didn't tell Jonnie how to reverse the process. Any Psychlo station out there could teleport new gas or even an army to Earth at will. That was the point that was giving him a headache.

“You're not very chatty,” said Ker, circling to land at the old defense base, going dead slow because of loose machinery. Jonnie came out of it. He pointed at the button camera that hung around his neck.

“Forget it,” said Ker to his astonishment. “They only have a range of about two miles.” He pointed at his work jacket pocket flap. A much smaller button camera with the symbol of the company on it was actually serving as a real button.

“Not five or more?” asked Jonnie.

“Crap no,” said Ker. “The security measures of this company are a pain. There's no recorder in this plane. I checked. What the splintered asteroid are we doing hauling this machinery over to this old defense base?” He looked down. “It doesn't even look like a defense base anyway.”

And it didn't. It was just some buildings, not even a landing field. No bunkers anyone could see. Some kind of a strange series of pointed things standing up at one end.

"Terl gives the orders,” said Jonnie, a bit resigned.

“Blast, no. These weren't Terl's orders. I saw them. They were signed by the head of the planet. Terl was even complaining. He said he wondered whether old Numph had gone off his computers.”

It gave Jonnie new data, but not what Ker thought. Terl was covering his tracks. This was Terl's project. It made him uneasy.

“This stuff,” said Ker, with a backward jerk of his head, “is supposed to be practice equipment. But for who? It 's perfectly good mining equipment. Hold on, we're going to land.” He punched the console buttons and the freighter crept down and landed easily and level.

Ker put on his face mask. “Another funny thing. There's no supply of breathe-gas with any of this stuff. Just what was left in their tanks. You're the only one I know that can operate these machines without breathe-gas in the canopies. You going to operate all these machines?” He laughed. “It’d sure run your butt off! Let's unload.”

They spent the next hour lining the machines up in an open field near the largest building. There were drillers and flying platforms, cable reelers, ore netters, blade scrapers, and a single transport truck. With the items brought in earlier loads there were over thirty machines now.

“Let's prowl,” said Ker. “We been fast. What's in this big building?”

It consisted only of rooms, rooms, and rooms. Each with bunks and lockers. There were what may have been washrooms. Ker was prowling for loot. But broken windows and wind and snow had not left much. Dust and indistinguishable debris were thick.

“Already been prowled,” was Ker's finding. “Let's look elsewhere.”

Ker clumped through the entrance of another building. Jonnie saw that it had been a library, but without Chinko protection it was mainly litter. A thousand years of cockroaches had dined on paper.

A queer, broken structure that once had had seventeen points– Jonnie counted them– seemed to have been some kind of a monument. Ker entered a door that was no longer there. A cross was still hanging on a wall.

“What's that thing?” said Ker. Jonnie knew it was a church cross. He said so.

“Funny thing to have in a defense base,” said Ker. “You know, I don't think this was a defense base. More like a school.”

Jonnie looked at Ker. The midget Psychlo might be thought dim-witted, but he was dead on the mark. Jonnie did not tell him there were signs all over the place that said “United States Air Force Academy.”

They wandered back to the freighter. “I bet we're establishing a school,” said Ker. “I bet that's what it is we're doing. But who's going to be taught? Not Psychlos with no breathe-gas, that's for sure. Put up the ramps, Jonnie, and we'll get out of here.”

Jonnie did, but he didn't climb up to the cockpit. He looked around for water and firewood. He had an idea he'd be camping out here. Yes, there was a stream coming down from a

nearby snow-capped peak. And there was plenty of firewood in the trees.

He walked out and looked at the trench where the last battle had been fought against the Psychlos. The grass was tall and waving in a lonesome-sounding wind.

He climbed to the freighter cockpit, deeply troubled.

At evening when he opened the cage, Terl sounded excited. “Tell your horses and females goodbye, animal. Tomorrow at dawn we're going on a long trip.”

Jonnie stopped with his arms full of the firewood he had been taking in. “How long?”

“Five days, a week. It depends,” said

Terl. “Why do you want to know?”

“I have to leave them food...a lot of things.”

“Oh,” said Terl indifferently. “Am I going to have to stand here and wait?” He made up his own mind. He locked up the cage again and turned on the juice. "I’ll come back later.” He rumbled off hurriedly.

Well, here it goes, Jonnie told himself.

What devilry was going to take place now?

Fortunately, that day he had gotten a fat young bull. He swiftly went about his work. He quartered it and rolled up two quarters in the hide, putting it outside the door.

"Chrissie!" he called. “Put me together enough smoked meat for a week. Also think about what you'll need for that time.”

“You're leaving?” Was there a trace of panic in Chrissie's voice?

“Just for a little while.”

Both girls looked apprehensive. They seemed so forlorn in there. Jonnie cursed to himself. "I’ll be sure to come back,” he said. “Get busy with the food.”

He inspected Blodgett's wound. Blodgett could walk now, but torn muscles had ended her running days.

The grazing problem for the horses was a little rough. He did not want to turn them loose, but he couldn't stake them to a week's grazing all in one spot. He finally settled it by letting them loose but instructing Pattie to call them to the barrier a couple of times a day to talk to them. Pattie promised she would.