This book’s underlying premise isn’t really my thing. The escape of the remnants of the Posleen works for me, and I think holds together. However, I’m unconvinced by a religious mission setting out after the Posleen to convert them to one of the Earth religions. That just seems a bit far fetched to me. However, this book is rescued by the insights into the Posleen’s history that it offers. Its worth wading through the other stuff that isn’t all that interesting just to find out a bit more about how the characters ended up in this state.