“All those childless protectors seeking a mission in life. A space industry to build ships designed for one job. Something could happen to Phssthpok, you know. An accident. Or he might lose the will to live, halfway here.”

Roy saw it then. “They’d send another ship.”

“That they would. Even if he got here, Phssthpok could use some help searching a volume thirty light years in radius. Whoever followed Phssthpok wouldn’t aim directly for Sol; Phssthpok would have searched Sol by the time he got here. He would aim to the side, away from Phssthpok’s obvious area of search. I figured that would give me a few extra years,” said Brennan. “I thought they’d send another ship almost immediately. I was afraid I wouldn’t be ready.”

“Why would it take them so long?”

“I don’t know.” Brennan made it sound like an admission of guilt. “A heavier cargo pod, maybe. Breeders in suspended animation, in case we died out over two and a half million years.”

Alice said, “You said you’d been watching—”

“Yah. A sun doesn’t burn fuel quite like a Bussard ramjet. There’s a constriction and a hell of a lot of heat, then the gas expands into space while it’s still fusing. A Bussard ramjet will put out a lot of funny chemicals: high-energy hydrogen and helium, lithium radicals, some borates, even lithium hydride, which is generally an impossible chemical. In deceleration mode those all go out in a high-energy stream at nearly lightspeed.

“Phssthpok’s ship worked that way, and I didn’t expect they’d fool with his design. Not just because it worked, but because it was the best design they could get. When you’re as bright as a Pak, theres only one right answer for a given set of tools. I wonder if something happened to their technology after Phssthpok left. Something like a war.” He pondered. “Anyway, I’ve found funny chemicals in Saggitarius. Something’s coming.”

Roy dreaded to ask. “How many ships?”

“One, of course. I haven’t actually found the image, but they’d have sent the second ship off as soon as they built it. Why wait? And maybe another ship behind it, and another behind that. I’ll search them out from here, while I’ve still got my quote telescope unquote.”

“Then what?”

“Then I’ll destroy as many ships as there are.”

“Just like that?”

“I keep getting that reaction,” Brennan said with some bitterness. “Look: If a Pak knew what the human race was like, he’d try to exterminate us. What am I supposed to do? Send him a message, ask for truce? That information alone would tell him enough.”

Alice said, “You might convince him you were Phssthpok.”

“Probably could at that. Then what? He’d stop eating, of course. But first he’d want to deliver his ship. He’d never believe we’ve already developed the technology to make artificial monopoles, and his ship is the second of its kind in this system, and we might need the thalium oxide too.”

“Um.”

“Um,” Brennan mimicked her. “Do you think I like the idea of murdering someone who came thirty-one thousand light years to save us from ourselves? I’ve been thinking this through for a long time. There’s no other answer. But don’t let that stop you.” Brennan stood up. “Think it through. While you’re at it, you might as well explore Kobold too. You’ll own it eventually. All of the dangerous things are behind doors. Have a ball, swim where you find water, play golf if you like. But don’t eat anything, and don’t open any doors. Roy, tell her about the Bluebeard legend.” Brennan pointed over a low hill. “That way, and through the garden, and you come to my laboratory. I’ll be there when you want me. Take your time.” And he went, not strolling, but running.

They looked at each other.

Alice said, “Do you think he really meant it?”

“I’d like to,” said Roy. “Generated gravity. And this place. Kobold. With gravity generators we could move it into the solar system, maybe, and set it up as a disneyland.”

“What did he mean about — Bluebeard?”

“He meant, ‘Really don’t open any doors.’ ”

“Oh.”

Given an unlimited choice of direction, they chose to follow Brennan over the hill. They did not catch sight of him again. Kobold had the sharply curved horizon of any small asteroid, at least from the outer curve of the toroid.

But they found the garden. Here were fruit trees and nut trees and vegetable patches in all stages of bloom. Roy pulled up a carrot, and it brought back a memory: he and some cousins, all about ten years old, walking with Greatly ’Stelle in the small vegetable garden on her estate. They’d pulled carrots, and washed them under a faucet…

He dropped the carrot without tasting it. He and Alice walked beneath the orange trees without touching them. In fairyland one does not lightly ignore the command of the resident warlock… especially as Roy was not sure that Brennan understood the power of the temptation to disobey.

A squirrel darted into a tree as they came near. A rabbit looked at them from a row of beets.

“it reminds me of Confinement Asteroid,” said Alice.

“It reminds me of California,” said Roy. “Except for the way the gravity bends around. I wonder if I’ve been here before.”

She looked at him sharply. “Do you remember any thing?”

“Not a thing. It’s all strange. Brennan never mentioned the kidnappings at all, did he?”

“No. He… may think he doesn’t have to. We must have it all figured out, because we’re here. If Brennan thinks in pure logic, then he’d just be covering old ground, as if we’ve already talked it all out.”

Beyond the garden they could see the topmost tower of a medieval castle, almost on its side from this perspective. Brennan’s laboratory, no doubt. They looked, then turned away.

The land grew wilder, became a stretch of California chaparral. They saw a fox, ground squirrels, even a feral cat. The place was lousy with wildlife: like a park, except for the way it bent.

On the inner curve of the toroid they stood beneath the grassy sphere, looking up at their ship. The great tree pointed its branches at them. “I could almost reach those branches,” said Roy. “I could climb down.”

“Never mind. Look there.” She pointed around the curve of the donut.

Where she pointed was a flowing stream, and a waterfall that fell up out of the middle, fell from the major section of Kobold to the grassy sphere.

“Yah. We could get to the ship, if we wanted to take that fall.”

“Brennan has to have a way to get from here to there.”

“He did say, ‘Swim in any water you find.’ ”

“But I can’t swim. You’d have to do it,” said Alice.

“Okay. Come on.”

The water was icy cold at first. Sunlight glittered blindingly off the water… and Roy wondered again. The sun was hot and bright overhead. But they’d have seen an atomic generator that size.

Alice looked down at him from the bank. “Are you sure you want to do this?”

“Pretty sure.” He laughed partly because he was shivering. “If I get in trouble, get Brennan. What do you want from the ship?”

“Clothes.” She was naked under the transparent pressure suit. “I kept wanting to cover myself with my hands.”

“From Brennan?”

“I know, Brennan’s sexless. Still.”

He asked, “Weapons?”

“No point.” She hesitated. “I tried to think of some way to check what Brennan’s been telling us. There aren’t any instruments on the ship that would do it. Still… you might try pointing the solar storm warning toward Saggitarius.”

Roy swam toward the waterfall. There was none of the sound of wild water. It could not be as dangerous as it ought to be.

Something brushed his ankle. He twitched and looked down. Silver flashed away from him through the water. A fish had brushed his leg. That had never happened to him before.

He came to where water was falling up. He rested, treading water, letting it draw him in. There was a moment of disorientation, and then…