But by their treaty with the dominant power in the Milky Way this type of temporal tourism is illegal and could start the ultimate intergalactic conflict - in which trillions would die.

So, someone has to act, and act fast. The People's ultra-powerful supercomputer, God, is prepared to destroy the city - killing a quarter of a million human beings and wrecking Earth history - rather than risk war. Benny is understandably against the idea; she has her own daringly cunning plan: to travel back herself to the cradle of civilisation and avert the disaster. Unfortunately, she is given only one week in which to act. So, with the clock ticking, Benny must find the errant People, and get them back to their own galaxy - or face a catastrophe that could mean she will never have existed.