The seven-year-old son of the famous archeology professor Giorgio Bramante mysteriously disappears in the temple of the Persian god Mithra, whose cult was widespread at one time along with Christianity. The child could not be found. Out of grief, Bramante almost loses his mind and goes to prison for the murder of a student, whom he considers guilty of what happened. But then fourteen years pass, and someone begins to kill all the witnesses to the disappearance of the child, and does this in strict accordance with the cruel ritual of sacrifice to Mithra. Suspicion falls on a professor recently released from prison, but experienced detective Leo Falcone knows for sure: everything is not so simple. To unravel the chain of mysterious murders, he has to again raise the case of the disappearance of Bramante’s little son...