Maura Isles deals with death. As a pathologist in downtown Boston, she has seen more than her share of corpses. But never before has the body on the medical examiner's table been her own. There can be no denying the evidence though. The dead woman is her mirror image right down to the most intimate physical details. Even more chilling is the discovery that they share the same birth date and blood type. Then a DNA test confirms that Maura's mysterious double is indeed her twin sister, and suddenly an already bizarre murder investigation becomes a disturbing excursion into a past full of dark and deadly secrets ...

For untold years, the perfectly preserved mummy had lain forgotten in the dusty basement of Boston’s Crispin Museum. Dubbed “Madam X,” the recently rediscovered mummy is, to all appearances, an ancient Egyptian artifact. But medical examiner Maura Isles discovers a macabre message hidden within the corpse–horrifying proof that this “centuries-old” relic is instead a modern-day murder victim. When the grisly remains of two other women are found, it becomes clear to Maura and Boston homicide detective Jane Rizzoli that a maniac is at large. Now Maura and Jane must unravel a murderer’s twisted endgame before the Archaeology Killer adds another chilling artifact to his monstrous collection.

Can you really see evil when you look into someone's eyes? In a rundown house, a woman has been dismembered in an act of carnage that leaves veteran cops in shock. Drawn on the wall, in blood, are ancient symbols, and a mirror-image word in Latin that, translated, says: "I have sinned." Then a second woman is found butchered on Beacon Hill, just outside the home of the leader of the Mephisto Club, a secret society dedicated to the study of evil. On the door yet more ancient symbols have been scrawled. This is evil that the Boston PD has never encountered before. And the only way Maura Isles can defeat it is by turning to the people who understand the devil himself.