Inna lives with her dad and little brother in a small town. Her life changes when a new girl, Masha, comes to her school. They become friends. But Masha is murdered by a maniac serial killer, who kills teenage girls in the town. Inna goes to church for the funeral service. There she meets the priest's son Ilya, whose sister was also murdered.

Tanya Vasilevskaya, a graduate of the Belarusian State Pedagogical University, gets assigned to a small school in the agro-town of Mezhrechye. The situation is aggravated by the fact that a very young teacher is put in charge of the 11th grade, whose former mentor unexpectedly retires. All the students in this class are complex and difficult children, but one of them, Sergey Yanchuk, requires special attention after the death of his mother. Tanya will have to overcome doubts, professional inexperience, skepticism and ridicule to become a good homeroom teacher.