International intelligence officer Pavel Rudnev randomly finds his twin brother Andrei Poletaev, lost in childhood, who works as an ordinary investigator in the local police department. The heroes agree on a meeting, but the next day Poletaev is killed, mistaking for Rudnev. Pavel finds out that a mole is working in the department, which systematically destroys Pavel's entire detachment. In order to find and neutralize the mole, the hero is forced to use Poletaev's personality as a cover - to investigate cases for him in cases at the local police station, to play the role of an exemplary husband and good father.