Esenya is a law graduate living in Moscow. After a tragedy strikes at her graduation party, she gets interested in a mysterious major Meglin, who is a legend when it comes to catching criminals.
Esenya has serious doubts about Meglin after what happened in Lipetsk, but she agrees to help him with another case. This time they are looking for a missing teenager. They also visit some old acquaintances of Meglin's.
When Esenya discovers a surprisingly high number of missing children in the town of Mikhaylovsk, she asks Meglin to accompany her there and investigate. The clues lead them to a local hiking club.
In the town of Troitsk a teenager is accused of murdering his father and stepmother. Esenya and Meglin investigate and the boy denies killing anyone. At the same time, Esenya learns new facts about the murder of her mother.
Esenya and Meglin investigate the death of a young woman whose naked body was found hanged. The clues lead them to the faculty of psychology at a local university. Meglin's illness becomes more and more serious.
Esenya and Meglin investigate a series of particularly gruesome murders. It seems that the killer murders people he deems guilty, using their "sins" against them.
Esenya and Meglin travel to Nizhny Novgorod to investigate a serial killer who poses corpses of young women with flowers. Meglin reveals a part of his past to Esenya.
Esenya and Meglin investigate a dead child. Zhenya asks Meglin for help with a possible serial killer of old women. Sasha is trying to find the man responsible for Anya's death. Esenya's father wants Meglin to stop working with her.
Esenya and Meglin travel to Serpukhov to investigate the murder of a female police officer. While searching for the killer they visit a psychiatric hospital, which causes Meglin to think about his own illness.
In Zaslavsk, a teenager goes on a killing spree in his school. After being surrounded by the police, he says he won't talk with anyone but Meglin. Meglin remembers his past.
Esenya and Meglin investigate a killer setting his victims on fire. Esenya meets with a woman she believes may know something about Meglin's past. She also confronts her father.
Meglin is determined to kill the murderer set loose by Esenya's father. He also takes Esenya to a "backup copy" of his archive, where she learns the truth about her mother.
