Ancillary Mercy - Ann Leckie (Book 3)

For a moment, things seemed to be under control for Breq, the soldier who used to be a warship.

Then a search of Athoek Station's slums turns up someone who shouldn't exist and a messenger from the mysterious Presger empire arrives, as does Breq's old enemy, the divided, heavily armed, and possibly insane Anaander Mianaai - ruler of an empire at war with itself. Breq could flee with her ship and crew, but that would leave the people of Athoek in terrible danger. Breq has a desperate plan.

The odds aren't good, but that's never stopped her before.