Ancillary Justice is a space opera set thousands of years in the future, where the principal power in human space is the expansionist Radch empire. The empire uses space ships controlled by AIs, who control human bodies ("ancillaries") to use as soldiers.
The narrative begins twenty years after the disappearance of a Radch starship, the Justice of Toren, when the sole surviving ancillary (and a fragment of the Justice of Toren's consciousness), Breq, encounters an officer, Seivarden, who had been a lieutenant on the Justice of Toren 1,000 years earlier. The plot switches between two strands: Breq's "present-day" quest for justice for the Justice of Toren's destruction and flashbacks from 19 years earlier when the Justice of Toren was in orbit around the planet of Shis'urna, which was being formally brought into the Radchaai empire.
