Nursing home employee Irina Golenkova was found with her throat cut in her bathroom. Her husband does not inspire confidence in the investigators, because, according to the acquaintances of the murdered woman, her husband often raised his hand against her. Suddenly, stories of mysterious murders related to the Golenkov family begin to surface. Under mysterious circumstances, the driver of the nursing home, the son-in-law of one of the patients, Irina's colleague, died ... All these cases are united by one circumstance, which becomes the main clue: the killer is left-handed.

Under mysterious circumstances, the popular radio host Semyon Bessonov disappears. From a conversation with colleagues and relatives, Loginov and Petrovskaya learn about the severe depression in which Bessonov was. His condition was aggravated by the impending dismissal. The confession of his wife did not make it easier for the investigators. It turns out that Semyon has already made an attempt to commit suicide.