What everybody wanted to know was whether there was any way of travelling from one universe to another. Between any pair of universes there was more than just empty hyperspace; there was a thing called an energy grid. It was useful - strands of it could help power ships, and it had been used as a weapon - but it was also an obstacle, and - by all accounts so far - one which had proved impenetrable to intelligent investigation. Certain black holes appeared to be linked to the grid and perhaps therefore to the universe beyond, but nobody had ever made it intact into one, or ever reappeared in any recognisable form. There were white holes, too; ferociously violent sources spraying torrents of energy into the universe with the power of a million suns and which also seemed to be linked to the grid . . . but no body, no ship or even information had ever been observed appearing from their tumultuous mouths; no equivalent of an airborne bacteria, no word, no language, just that incoherent scream of cascading energies and super energetic particles.

The dream that every Involved had, which virtually every technologically advanced civilisation clove to with almost religious faith, was that one day it would be possible to travel from one universe to another, to step up or down through those expanding bubbles, so that - apart from anything else - one need never suffer the final fate of one’s own universe. To achieve that would surely be to Sublime, truly to Transcend, to consummate the ultimate Surpassing and accomplish the ultimate empowerment.

The River class General Contact Unit Fate Amenable To Change lay in space. It was locally stationary, taking its reference from the Excession. The Excession was equally static, taking its reference from the star Esperi. The entity sat there, a few light minutes away, a featureless dot on the skein of real space with a single equally dull-looking strand of twisted, compressed space-time fabric leading down to the lower layer of energy grid . . . and a second leading upwards to the higher layer.

The Excession was doing exactly what it had been doing for the past two weeks; nothing. The Fate Amenable To Change had carried out all the standard initial measurements and observations of the entity, but had been very forcefully advised indeed not to do any more; no direct contact was to be attempted, not even by probes, smaller craft or drones. In theory it could disobey; it was its own ship, it could make up its own mind . . . but in practice it had to heed the advice of those who knew if not more than it, better than it.

Collective responsibility. Also known as sharing the blame.