This book got a bit of publicity for the author's choice to make the language of the ruling empire (Radch) have only one pronoun, which defaults to female. So every character in the book is a "she" to the narrator, regardless of whether they actually are. This makes the first part of the book in particular a little confusing; it took me a while to figure out, and I'm still a bit confused about who exactly wasn't actually a "she". Which, I suppose, is an interesting way for the author to have made the point that it doesn't really matter, and also why NOT default to "she" as much as anything else?

Anyway, pronoun choices aside, the book's a very interesting SF story following the Justice of Toren, a sapient battle ship in the Radch military fleet. Justice of Toren is manifested in hundreds of "ancillaries", each ancillary being a formerly human person whose original personality has been removed, and whose body has been converted to use as essentially a remote tool for the ship. The ship inhabits hundreds of ancillaries all simultaneously in order to maintain a physical presence everywhere needed. This book is the story of one of them that has become separated from the ship (for reasons we eventually find out about half way through the book) and is now living independently, trying to be a person but with the memories of being a massive multi-consciousness battle ship thousands of years old. Which, not surprisingly, is taking some adjustment.

The story flips back and forth in time, mainly between the events leading up to getting separated from Justice of Toren, and the present time where our protagonist is on a journey related to the earlier event. Along the way it also meets several people it knew from when it was a ship and embarks on what seems like a particularly crazy mission for revenge.

It's hard to describe the plot too much without spoilers, but if you enjoy sapient ships and AI (like "The Ship Who Sang", or "Children of Time") and don't mind putting in a little mental effort into figuring out what's going on at the start of the book, it's a pretty unique set of characters and a very interesting galactic empire and set of challenges to overcome. I enjoyed it, but 4 stars rather than 5 as I did find it confusing in places and also most of the characters aren't particularly likeable, which is always a problem for me.

This is the first of a trilogy, and while the story wraps up pretty well without a suspenseful cliffhanger, it's still clear there will be more to come should you wish to pick up the next.