Yaroslavl, 1974. Two high-profile and violent crimes are taking place in the city. The investigation is being handled by the uncompromising investigator for particularly important cases of the prosecutor's office, Egor Tabolin. The threads of these crimes lead to one person — the head physician of the psychiatric hospital, Mikhail Nagornykh, and his deputy Vaganov, in whose hospital several mysterious deaths have occurred in recent years.