MGB agent Leo Demidov has been assigned to cover up a local murder.
A fellow agent in the MGB—the Soviet secret police—is claiming that his son was murdered, but the government refuses to acknowledge existence of murder… period. Leo is annoyed to have to deal with this, especially because it leads to the escape of Anatoly Brodsky, a veterinarian suspected of espionage Leo had been assigned to monitor.
After a brutal manhunt that ends with the murder of two of Brodsky's accomplices, Leo interrogates his prisoner. To his utter shock, Leo realizes that the man is completely innocent. This really throws him for a loop and forces him to take sick leave for several days. When he returns, he finds that Brodsky has been executed—and, far more shockingly, it turns out that Brodsky has named Leo's wife Raisa as an accomplice in his confession.
Leo stands up for his wife's innocence—a decision that gets him fired from the MGB and sent to the local militia in Voualsk. In Voualsk, he meets General Nesterov, who shows Leo a local murder that shares shocking similarities to the one back is Moscow. Leo and Raisa investigate on their own and discover another body, which leads Nesterov to start a witch-hunt for local gay men so that they can be used as scapegoats. Angry, Leo confronts Nesterov and demands that they do a real investigation.
With that, both parties split up and search for evidence. Nesterov heads south and discovers that most of the murders are taking place near the border with Ukraine—and there are a ton of murders. Leo and Raisa, on the other hand, head to Moscow. Unfortunately, everyone is arrested after the MGB—furious that our heroes are taking justice into their own hands—catches on to their plans.
Luckily, however, Leo and Raisa perform a death-defying escape and make their way to the border, where they discover the serial killer's identity. In an insane twist, the killer turns out to be Leo's long-lost brother, Andrei. Guess what? Leo had been kidnapped in his youth.
Leo confronts Andrei, but he is hesitant to kill him. Although Andrei saves Leo's life after Leo's former lieutenant tries to ruin the reunion, Leo finds he has no choice—so he and Raisa pull the trigger together.
Afterwards, Leo is reinstated in the MGB and placed in charge of a new homicide division in Moscow. He and Raisa also adopt the daughters of Brodsky's murdered accomplices.