Rusel was woken from his long slumber by the face of a boy, a face twisted with anger - an anger directed at him.

In retrospect Rusel should have seen the rebellion coming. All the indicators had been there: the drift of the transients’ social structures, the gathering tensions. It was bound to happen.

But it was so hard for him to pay attention to the brief lives of these transients, their incomprehensible language and customs, their petty concerns and squabbling. After all, Hilin was a boy of the forty-fifth generation since launch: forty-five generations. Lethe, nearly a thousand years . . .

The exploits of Hilin, though, forced themselves on his attention.

Hilin was sixteen years old when it all began. He had been born in Diluc’s corridor-village.

By now the Autarchs of the different villages had intermarried to form a seamless web of power. They lived on average twice as long as their subjects, and had established a monopoly on the Ship’s water supply. A water empire ruled by gerontocrats: their control was total.

Hilin was not one of the local Autarch’s brood; his family were poor and powerless, like all the Autarch’s subjects. But they seemed to accept their lot. As he played in corridors whose polymer floors were rutted by generations of passing feet, Hilin emerged as a bright, happy child. He seemed compliant when he was young, cheerfully swabbing the bulkheads when it was his turn, and accepting the cuffs of his teachers when he asked impudent questions.

He had always been oddly fascinated by the figure of Rusel himself - or rather the semi-mythical presence portrayed to the villagers through the cycling Virtual storyboards. Hilin soaked up the story of the noble Elder who had been forced to choose between a life of unending duty and his beloved Lora, eventually becoming an undying model to those he ruled.

As he had grown, Hilin had flourished educationally. At fourteen he was inducted into an elite caste. As intellectual standards declined, literacy had largely been abandoned, and ancient manuals had anyhow crumbled to dust. So these monkish thinkers now committed to memory every significant commandment regarding the workings of the Ship and their own society. You would start on this vital project at fourteen, and wouldn’t expect to be done until you were in your fifties, by which time a new generation of rememberers was ready to take over anyhow.

Rusel dryly called these patient thinkers Druids: he wasn’t interested in the transients’ own names for themselves, which would change in an eye-blink generation anyhow. He had certainly approved of this practice when it emerged. All this endless memorising was a marvellous way to use up pointless lives - and it established a power-base to rival the Autarchs.

Again Hilin had flourished, and he passed one Druidic assessment after another. Even a torrid romance with Sale, a girl from a neighbouring village, didn’t distract him from his studies.