This is the last Nagata that I read although I understand this one is superseded by another novel called Edge. I have no interest in reading that. I have no interest in re-reading this one either (or any of this series), but I do have a decent enough recollection of it to say this was the best of the three I did read, and to give it a worthy rating.
The story could be a standalone since it's essentially unconnected with anything that preceded it and needs no connection with anything else. It tells the story of a group of astronauts in a spacecraft named the 'Null Boundary', who are running from an alien race known as the Chenzeme. The Chenzeme for reasons either unexplained or which I do not recall, are purging space of humans. Maybe they're terrified of the nano-tech that humans have unleashed? LOL!
There's some weird stuff that happens in this novel and some situations which make it interesting, but that's all I'm going to say about it. I do commend it as a worthy read although I have to say that after three of her novels, I'm really not feeling any need to read anything else by this author.