Marseille

It's Sergey Lezhnev's first day on his new ambulance team. The team rushes on a call from an apartment of a known activist Boyer. Police major Romashka is already working there, he asked to call this particular team to discuss details of a crime with Lezhnev: Boyer and his unknown friend were killed.

Criminals kidnap Sergey while his team was answering another call. Lesha Posadsky, a known crime lord, asks Sergey to find his lover's killer. Posadsky heard rumors about the paramedic's phenomenal abilities, and in return he is ready to do anything Sergey asks. 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.

An ordinary car explodes in a parking lot. A young girl manages to save a woman and two babies at the risk of her own life. There are many suspects, major Romashka constantly argues with colonel Andreev. They're both stunned when they see Lezhnev near the scene of the explosion.

The bomber is still not found. However, another explosive device was found nearby, and this time a school is in danger. Sergey manages to find contact with one of the residents, who is happy to help him, and they begin to go through possible theories of the crime. While solving this complicated problem, Sergey manages to help Margarita to bring her little sister to her senses.

Someone tries to kill Sergey during his regular morning jog. Major Romashka invites Sergey to his apartment for a straight talk and introduces him to his unusually large family. Risking his life, Sergey takes part in a colonel's Andreev complicated operation; to arrest a dangerous criminal. One of Lezhnev sister's ex-husbands takes Sergey to an apartment, where he finally may meet his mother.

Sergey is waiting for his mother in her rented apartment, but major Romashka comes instead and asks Serge for help. A travel agency director's child was kidnapped, and now criminals ask for ransom. Sergey cannot resist the temptation to solve the puzzle.