Criminal police inspector Sam Berger and his subordinates break into an abandoned house where, according to them, a maniac is holding a kidnapped fifteen-year-old girl. The house is empty, but they find a musty basement with blood and fingernail marks on the concrete floor. Contrary to the opinion of his superiors, the inspector is sure that the criminal has many victims, so he simultaneously conducts his own investigation, sometimes breaking the law. Berger has his own secret interest in this case: every time at the crime scene, the maniac leaves a message that only he can understand.