Ursula is born in 1910, dies immediately, and is born again. The book runs her life repeatedly through the century, each version diverging on small decisions.
It avoids becoming a puzzle because she never fully knows what is happening. There is only a sense of dread attached to certain staircases and certain men, which is a better mechanism than giving her explicit memory would have been.
The Blitz sections are the strongest writing in it.
Read January 2016.