This habitat, Confluence, was created by the Preservers who have left the galaxy. They uplifted 10,000 species, but after they left, the species fought so much that the story starts at a point relatively equivalent to the late 1700s with half the habitat glassy from nukes. There are still machines that can be used, but few and they die quickly.
Yamamanama, usually called Yama, is in a bloodline that hasn't been seen in a long time. He wants to know how to find his people, but in the meantime finds other people and does good things and saves as many people as he can. There's a revelation near the end that was obvious all the way through.
Even if McAuley had stuck with the SF mirage, I think these books would have been much better worked down to one book.