Yaroslavl, 1974. Two high-profile cases are taking place in the city: first, a recidivist thief Lukin, nicknamed Burelom, is killed with an awl in the ear, and then a mentally ill physicist Kalenov cuts off the head of a neighbor and brings it to the police. Egor Tabolin, an investigator for particularly important cases, is taking over the investigation of the case. He is convinced that twice Hero of the Soviet Union pilot Timofey Kretov, who previously confessed to the murder of Lukin, is innocent, and the woman was obviously killed for a reason. Tabolin realizes that both crimes are connected by an invisible thread that leads to a local psychiatric hospital run by the head physician Mikhail Nagornykh and his deputy Viktor Vaganov. Now the main task of the investigator is not only to sort out these complicated cases and understand what the hospital management has to do with the crimes, but also to catch the elusive killer and achieve capital punishment for the perpetrators.