A brutal killer is on the streets of Rome. He leaves no trace. And shows no mercy. A series of gruesome murders leaves the police force in Rome reeling, with no real clues or hard evidence to follow. Assigned to the case is Sandra Vega, a brilliant forensic analyst, struggling to come to terms with the crimes and her own past. Sandra's shared history with Marcus, a member of the ancient Penitenzeri - a unique Italian team, linked to the Vatican, and trained in the detection of true evil, means that the two are brought together again in the pursuit of a malignant killer. Soon Marcus and Sandra notice the emergence of a disturbing pattern running alongside the latest killings - and every time they think they have grasped a fragment of the truth, they are led down yet another terrifying path.