This is book number 2 in the Imperial Radch series.
The sequel to Ancillary Justice, winner of the Hugo, Nebula, British Science Fiction, Locus, and Arthur C. Clarke Awards
Breq is a soldier who used to be a warship. Once a weapon of conquest controlling thousands of minds, now she has only a single body and serves the emperor.
With a new ship and a troublesome crew, Breq is ordered to go to the only place in the galaxy she would agree to go: Athoek Station, where she's to protect the family of a lieutenant she once knew-a lieutenant she murdered in cold blood.