Not even the icy temperatures of a typical New England winter can match the bone-chilling scene of carnage discovered in the early morning hours at the chapel of Our Lady of Divine Light. Within the sanctuary walls of the cloistered convent, now stained with blood, lie two nuns - one dead, one critically injured; victims of an unspeakably savage attacker. The brutal crime appears to be without motive, and the elderly nuns in residence can offer little help in the police investigation. But medical examiner Maura Isles' autopsy of the dead woman yields a shocking surprise: twenty-year-old Sister Camille, the order's sole novice, had given birth before she was murdered. The disturbing case takes a stunning new turn when another woman is found murdered in an abandoned building, her features obliterated. Together, Isles and homicide detective Jane Rizzoli uncover an ancient horror that connects these terrible slaughters. As long-buried secrets come to light, Maura Isles finds herself drawn inexorably toward the heart of an investigation that strikes closer and closer to home, and toward the dawning revelation - too shattering to consider - of the killer's identity.