The conclave to elect a successor to the deceased Pope suddenly turns into a nightmare. The mysterious criminal not only kills the cardinals one by one, but also performs a cruel ancient ritual on his victims. The murder case is being handled by a very unusual team: doctor of criminology Paola Dicanti and her partners - a police inspector, the superintendent of the Vatican intelligence services and their volunteer assistant - a Catholic priest with a mysterious past and the skills of a secret agent. They understand that something strange is happening. The Vatican denies that the murders of cardinals ever took place... To find the killer, Paola and her assistants have to penetrate the “holy of holies” of the Vatican - a labyrinth of dark secrets, intrigues and conspiracies...