The people who lived in it, riding out to the stars, were mostly scientists and their children. The ship had to operate far more than fifty years, if they were all to stay alive. The time was almost over, and the ship’s vast intricate systems were starting to break down, to fail. Youngsters trained as engineers and technicians had all the learning that the tapes could provide. But could they keep the ship going indefinitely?

A month ago it was the main power generator that failed, and they began to ration electrical power. Last week it was a pump in the hydroponics section; if they hadn’t been able to repair the pump they would have lost a quarter of their food production, plus the even more important oxygen-recycling ability of the green plants that grew in the long troughs of chemical nutrients. And now the fire. Fifty people dead.

Will any of us make it?

A soft tapping at his door. Fingernails on plastic. Valery.

“Come in,” Larry said, getting up from his chair.

The door slid open and she stood there framed in the light from the corridor.

Valery looked small, but she was actually almost Larry’s height, and he had known since their childhood together that she was as tough and supple as plastisteel. Her face was broad, with high Nordic cheekbones and wide, always-surprised-looking eyes. Changeable eyes; sometimes blue, sometimes green, sometimes something else altogether. Very fair skin with a scattering of freckles. Very, very pretty.

She was wearing a simple white jumpskirt and blouse. Like most of the girls aboard the ship, Valery made her own clothes.