Season 1

1996. A new executioner, Konstantin Volkov, is transferred from the city of Kimry to a special-regime prison in the Russian Far East. He meets his colleagues—Sasha Rybkin and Roma Savelyev—along with the local prosecutor and the prison warden. Volkov is brought up to speed on operations and shown how the penitentiary facility runs. The prison holds five inmates awaiting the death penalty. Volkov provides painkillers to the suffering "Professor"—a convict sentenced for the murder and dismemberment of five young women. His colleagues quickly come to respect the principled Kostya. Sasha is preparing for his wedding to Natasha, but tragedy strikes his fiancée after her bachelorette party.

Police officers arrive at Natasha's home. According to witness statements, she was seen in the company of the missing Vadik. Yulya seeks professional advice from her husband, prison doctor Petya. He turns to the incarcerated Doctor for help, and the doctor's advice proves useful. Katya has a fight with her mother-in-law and leaves home. Petya picks up his son from a classmate's house and meets the boy's mother. Kostya has a private conversation with the Professor and records it on a dictaphone. An idea begins to form for the executioner: the father of one of the victims has approached him and Sasha with a request to kill the maniac. The $500 offer is tempting, but Kostya is convinced they can make far more money inside the prison.

Prison doctor Petya brings home the dollars earned from the Professor's execution. His ailing wife Yulya refuses handouts from the husband who infected her, while his mistress gratefully accepts the money. Natasha learns she is pregnant and is unsure who the father of the unborn child might be—possibly the murdered rapist. The prosecutor doubts that Kostya and his team will pull off selling an execution in the prison so easily next time. The prosecutor's wife discovers a stack of dollars at her husband's home. Police uncover the body of Kotov, the man who approached Kostya and Sasha with the request to kill the Professor. The guards travel to another city to speak with the relatives of the Doctor's victims.

A friend of Andrey's named Oleg approaches Sasha and Kostya. He wants revenge for his comrade and demands they kill the Doctor. Oleg threatens to go to the police if his request isn't fulfilled. Kostya and Sasha beat Oleg and take him back to their town. Prison doctor Petya starts taking medication to suppress his urge to have sex with every woman around him. Roma visits Nina and confesses his love; he plans to take Kostya's wife to California. Natasha tells her mother about the pregnancy and says her husband doesn't want the child. Her mother strongly urges her to get an abortion. The investigator handling Kotov's murder case is closing in on the prison staff.

The prosecutor, Roma, Sasha, and the doctor devise a plan to execute the Doctor. The killing is scheduled for the night after Andrey's housewarming party. Kostya finds out about everything, but they intend to carry out the murder without him. A rift forms within the team. Natasha has had an abortion without telling her husband. She takes a turn for the worse and is rushed to intensive care. Sasha gets heavily drunk. Prison doctor Petya tries to extract from the Doctor whether he has any contacts who could help cure HIV. Kostya locks the intoxicated Sasha in a cell and goes to the prison warden. He wants to file a report on his colleague. Several conflicts erupt at Andrey's housewarming party.

While Sasha sleeps soundly, Petya, Roma, and Andrey try to figure out how investigator Zhuchkov tracked them down. There's definitely a traitor among them who sold them out—but who? The prison warden arrives at Petya, Roma, and Andrey's place and demands they explain what's really going on in his facility and who organized it all. The trio insists that Volkov came up with the whole thing. Meanwhile, Kostya is sitting in a police cell. The next morning, the warden visits Zhuchkov, whom Kostya has already briefed on the situation. The investigator's colleagues release Volkov. The warden and Kostya meet and agree not to act against each other. Volkov is sent on leave, while the warden deals with the investigator.

The prison warden pays a visit to the prosecutor and delivers a stern, educational talk to him. Natasha returns home and finds the fur coat that Sasha bought. Katya stops by to visit her and reveals the real source of income for their husbands. The two women then go to Yulya's place and inform her about her husband's business. Natasha's mother is desperate to meet with investigator Zhuchkov to find out why her son-in-law is still free despite being suspected of two murders. Masha helps Nina sneak out of the house to meet Roma, but the executioner fails to show up at the appointed time. The warden speaks with a colleague from a neighboring penitentiary facility and introduces strict new rules and order at his own institution.

Prison doctor Petya extracts from the Doctor the recipe for a lethal cocktail he used to eliminate his victims. In exchange, the death-row inmate is transferred to a hospital for treatment—so the Doctor will live a while longer. The prison warden spots Japanese visitors in town and offers them the chance to kill one of the condemned prisoners, with generous payment. Meanwhile, they need to deal with Kostya once and for all. The comrades' choice falls on Sasha, who had a good relationship with Volkov. Sasha hesitates to deliver the fatal injection and turns to Natasha for help. If Kostya is eliminated, the illegal business inside the prison walls can thrive without any obstacles.