The storyline alternates between different time-points, the main character is an artificial intelligence of a ship, which is spread out in some parts of the story across different bodies. As we learn towards the end, the main antagonist is also a multi-body character, who on top of everything else is developing a split personality. And in most contexts the book does not differentiate between the genders of its characters, which just ends up highlighting your habits of thinking about people in terms of certain gender images, and makes the reading (justifiably) a bit difficult to the extent that you would want to reconstruct the characters visually in your mind while going through the story.
But in the end the second attempt (or actually third, because I ended up reading the first 100 pages twice on the second attempt) was successful and the book was quite enjoyable. A lot of it revolves around how an artificial intelligence that can control or inhabit several bodies would look like, how it would think and operate. And that on its own is an interesting subject that makes Ancillary Justice worth a read.