The series is set in 1990 in the provincial town of Polynsk, where Moscow psychologist Vyacheslav Shirokov arrives to confirm or refute the guilt of a man suspected of multiple murders. Shirokov is a true professional in his field, but his intelligence and attentiveness sometimes irritate the investigators who want to close the case as quickly as possible. Shirokov is forced to collaborate with investigator Bragin, who clearly dislikes him, but for Shirokov, the most important thing is to uncover the truth and find the criminal.