Paramedic Sergey Lezhnev uses his analytical abilities to solve crimes.

Criminals kidnap Sergey; crime lord Lesha Posadsky asks Sergey to find his lover's killer; Sergey agrees only when Posadsky promises to help him find his mother.

The mysterious death of a boxer in a ring, strange relations between a coach and an investigator, conversations about match fixing: these are the next problems major Romashka asks Sergey Lezhnev to help solve. However, Sergey is not very keen to solve this crime, because he finally found a small lead that might help him to find his mother.

Kolesik, on behalf of a powerful criminal Puchok, tries to frighten Sergey into helping him find a missing treasurer. Security Service colonel Andreev notices that he always meets Serge under strange circumstances, and decides to put together a file on Lezhnev. Major Romashka does not like this, but is unsure about making friends with Sergey just yet.

A car explodes in a parking lot, and a young girl manages to save a woman and children at the risk of her own life.

The bomber is still not found; another explosive device is found nearby, and this time a school is in danger.