A young woman emerges from a coma. Who is she, and why was she dumped unconscious in a hospital car park upon a dark night? She is unable to recall anything, even her name.

Then Ada Shaftsbury, a boisterous shoplifter she meets in a homeless hostel, takes up her cause and names her Rose. Peter Diamond is already investigating a suspicious death - a woman has plunged from the roof of Bath's Royal Crescent during a party and none of the guests seem to know who she is. Badgered by Ada and galvanised by another gruesome death, Diamond takes on the case, and is soon forced to admit that Rose is the key.

But she has disappeared and Diamond's own dark night is just beginning.