The TARDIS takes the Doctor and Rose to a disastrous destination in deep space — Justicia, a prison camp stretched over seven planets, where Earth colonies deal with their criminals.
Soon Rose finds herself locked up in a teenage borstal while the Doctor languishes in a scientific labour camp. Each is determined to find the other, and soon both Rose and the Doctor are risking their lives to escape in their distinctive styles.
But their dangerous plans are further complicated by some old enemies. But are they fellow prisoners as they claim, or are they staging a takeover for their own sinister purposes?