“We’re going to have to be smart to survive, on any timescale you care to think about. My dad says he thinks I went a little crazy, back when I was a kid. But I think I went a little sane. It was like waking up. It seems to me that everyone else is a little crazy, not me.” She was looking out over the city, and the last of the sunlight picked out her profile, her strong nose and chin.

He said, “Maybe you’re too sane. Nobody should be burdened with too much future.”

“I’m not so tough. I’m a twentieth-century baby like everybody else. Spoiled rotten. As soon as anything serious happened, I’d run round in circles.”

“I wouldn’t be so sure.”

The light was diminishing. The Moon grew brighter, as if to compensate, and she looked up at it.

“You know,” Henry said, “the project I was working on for NASA was about going back to the Moon. Looking for water ice there. I think it’s possible there is so much ice you could actually terraform the Moon.”

“Make it like the Earth.”

“Yes. Somewhere else for people to live. But my project got canned, and we may never know about the ice. Nobody’s going to the Moon any time soon. Least of all me.”

“Would you go if you had the chance?”

He grinned. “In those ropy World War Two rockets they fly? No, sir.”

“So you’re a childless man who wants to build a new world.”

“Oh. Sublimation, you think.”

“Could be.”

“And you’re a parlour psychoanalyst. Lucky me.”

She said, “You know, after I read that Heinlein story, I coloured in maps of the Moon, figuring out where the oceans and cities must once have been.”

He nodded. “How about that. So did I. We have something in common after all.”

“I was just a kid…”

He stared up at the Moon. “It would be a beautiful thing. A terraformed Moon. It would be much brighter. A twin of the Earth. And if you were on the Moon — well, with that low gravity, it would be like something out of H.G. Wells. The First Men In The Moon.”

“Umm.” She stood up, and brushed down her dress “And people call me crazy.”

“I never did.”

“But you thought it. I know why. I run a shop where people come and pick up the rocks, trying to feel their vibrations—”

“Now they’re the crazy ones.”

“Are they?” she said mildly. “But there’s a rock in my digital watch; its vibrations keep the time. And they vibrate rocks to send laser beams, all the way to the Moon. We live in a strange world. Come on. We’d better go down before it’s too dark. Although you’ll like the Northern Lights displays we’ve been getting since Venus…”

He unfolded his legs and stood.