This one moves into a completely different idea -- when Terry was "killed" at the end of the last book and became a "god," he gets a new kind of ouroborus that moves him not only in space, but in time. He keeps coming back to Jodenny at different parts of her life, but she never remembers the "eddy" in time that he's created. He becomes sicker and sicker and as the book advances, one of their old shipmates joins the ring movements.
Jodenny ends up in 19th century Australia, very pregnant, with their old shipmate, and eventually, in the last sentence, things are wrapped up. There's an epilogue that would give reason for more books.
I have to say that I would probably have been happier reading just the first book, which is milSF with a bit of the Australian background. The second and third books rely more and more on Australian ideas and history and less on SF.