Dr Maura Isles makes her living dealing with death. As a pathologist in downtown Boston, she has seen more than her share of corpses. But never before has the lifeless body on the medical examiner's table been her own. but there can be no denying the evidence: the dead woman before her and her close friend and colleague detective Jane Rizzoli is the mirror image of Maura. Even more chilling is the discovery that they share the same birth date and blood type. When a DNA test confirms that Maura's mysterious double is in fact her twin sister, an already bizarre murder investigation becomes a disturbing and dangerous excursion into past full of dark and deadly secrets. This is the fourth Jane Rizzoli-novel.