It took me at least an hour and almost as long to prove it, using a different sequence-and a third time, because the answers didn't match (I had forgotten to multiply by 5280, and had "miles" on one side and "feet" on the other-a no-good way to do arithmetic)-then a fourth time because my confidence was shaken. I tell you, the slide rule is the greatest invention since girls.

But I got a proved answer. Five and a half days. I was on Pluto.

Or maybe Neptune-

No, on Neptune I would not be able to jump to a twelve-foot ceiling; Pluto alone matched all facts. So I erased and computed the trip at one gravity, with turnover.

Fifteen days.

It seemed to me that it ought to take at least eight times as long at one gee as at eight-more likely sixty-four. Then I was glad I had bulled my way through analytical geometry, for I made a rough plot and saw the trouble. Squared time cut down the advantage-because the more boost, the shorter the trip, and the shorter the trip the less time in which to use the built-up speed. To cut time in half, you need four times as much boost; to cut it to a quarter, you need sixteen times the boost, and so on. This way lies bankruptcy.

To learn that I could get home in about two weeks at one gravity cheered me. I couldn't starve in two weeks. If I could steal a ship. If I could run it. If I could climb out of this hole. If- Not "if," but "when!" I was too late for college this year; fifteen more days wouldn't matter.

I had noticed, in the first problem, the speed we had been making at skew-flip. More than eleven thousand miles per second. That's a nice speed, even in space. It made me think. Consider the nearest star, Proxima Centauri, four and three-tenths light-years away, the distance you hear so often on quiz shows. How long at eight gees?

The problem was the same sort but I had to be careful about decimal points; the figures mount up. A lightyear is-I had forgotten. So multiply 186,000 miles per second (the speed of light) by the seconds in a year (365.25 x 24 x 3600) and get-5,880,000,000,000 miles -multiply that by 4.3 and get- 25,284,000,000,000 Call it twenty-five trillion miles. Whew!

It works out to a year and five months-not as long as a trip around the Horn only last century.

Why, these monsters had star travel!

I don't know why I was surprised; it had been staring me in the face. I had assumed that Wormface had taken me to his home planet, that he was a Plutonian, or Plutocrat, or whatever the word is. But he couldn't be.

He breathed air. He kept his ship warm enough for me. When he wasn't in a hurry, he cruised at one gee, near enough. He used lighting that suited my eyes. Therefore he came from the sort of planet I came from.

Proxima Centauri is a double star, as you know if you do crossword puzzles, and one is a twin for our own Sun-size, temperature, special pattern. Is it a fair guess that it has a planet like Earth? I had a dirty hunch that I knew Wormface's home address.

I knew where he didn't come from. Not from a planet that runs a couple of centuries in utter airlessness with temperatures pushing absolute zero, followed by a "summer" in which some gases melt but water is solid rock and even Wormface has to wear a space suit. Nor from anywhere in our system, for I was sure as taxes that Wormface felt at home only on a planet like ours. Never mind the way he looked; spiders don't look like us but they like the things we like-there must be a thousand spiders in our houses for every one of us.

Wormface and his kin would like Earth. My fear was that they liked it too much.

I looked at that Proxima Centauri problem and saw something else. The turn-over speed read 1,110,000 miles per second, six times the speed of light. Relativity theory says that's impossible.

I wanted to talk to Dad about it. Dad reads everything from The Anatomy of Melancholy to Acta Mathematica and Paris-Match and will sit on a curbstone separating damp newspapers wrapped around garbage in order to see continued-on-page-eight. Dad would haul down a book and we'd look it up. Then he would try four or five more with other opinions. Dad doesn't hold with the idea that it-must-be-true-or-they-wouldn't-have-printed-it; he doesn't consider any opinion sacred-it shocked me the first time he took out a pen and changed something in one of my math books.

Still, even if speed-of-light was a limit, four or five years wasn't impossible, or even impractical. We've been told for so long that star trips, even to the nearest stars, would take generations that we may have a wrong slant. A mile of lunar mountains is a long way but a trillion miles in empty space may not be.

But what was Wormface doing on Pluto?

If you were invading another solar system, how would you start? I'm not joking; a dungeon on Pluto is no joke and I never laughed at Wormface. Would you just barge in, or toss your hat in first? They seemed far ahead of us in engineering but they couldn't have known that ahead of time. Wouldn't it be smart to build a supply base in that system in some spot nobody ever visited?

Then you could set up advance bases, say on an airless satellite of a likely-looking planet, from which you could scout the surface of the target planet. If you lost your scouting base, you would pull back to main base and work out a new attack.

Remember that while Pluto is a long way off to us, it was only five days from Luna for Wormface. Think about World War II, back when speeds were slow. Main Base is safely out of reach (U.S.A./Pluto) but only about five days from advance base (England/The Moon) which is three hours from theater-of-operations (France-Germany/Earth). That's a slow way to operate but it worked for the Allies in World War II.

I just hoped it would not work for Wormface's gang.

Though I didn't see anything to prevent it.

Somebody chucked down another can-spaghetti and meat balls. If it had been canned peaches, I might not have had the fortitude to do what I did next, which was to use it for a hammer before I opened it. I beat an empty can into a flat narrow shape and beat a point on it, which I sharpened on the edge of the catch basin. When I was through, I had a dagger -not a good one, but it made me feel less helpless.

Then I ate. I felt sleepy and went to sleep in a warm glow. I was still a prisoner but I had a weapon of sorts and I believed that I had figured out what I was up against. Getting a problem analyzed is two-thirds of solving it. I didn't have nightmares.

The next thing tossed down the hole was Fats.

Skinny landed on him seconds later. I backed off and held my dagger ready. Skinny ignored me, picked himself up, looked around, went to the water spout and got a drink. Fats was in no shape to do anything; his breath was knocked out.

I looked at him and thought what a nasty parcel he was. Then I thought, oh, what the deuce!-he had massaged me when I needed it. I heaved him onto his stomach and began artificial respiration. In four or five pushes his motor caught and he was able to breathe. He gasped, "That's enough!"

I backed off, got my knife out. Skinny was sitting against a wall, ignoring us. Fats looked at my feeble weapon and said, "Put that away, kid. We're bosom buddies now."

"We are?"

"Yeah. Us human types had better stick together." He sighed wretchedly. "After all we done for him! That's gratitude."

"What do you mean?" I demanded.

"Huh?" said Fats. "Just what I said. He decided he could do without us. So Annie doesn't live here any more."

"Shaddap," the skinny one said flatly.

Fats screwed his face into a pout. "You shaddap," he said peevishly. "I'm tired of that. It's shaddap here, shaddap there, all day long-and look where we are."

"Shaddap, I said."

Fats shut up. I never did find out what had happened, because Fats seldom gave the same explanation twice. The older man never spoke except for that tiresome order to shut up, or in monosyllables even less helpful. But one thing was clear: they had lost their jobs as assistant gangsters, or fifth columnists, or whatever you call a human being who would stooge against his own race. Once Fats said, "Matter of fact, it's your fault."