The director of the elite school Ageev is killed near the garbage chute with a shot in the back of the head. After talking to the Ageyevs' neighbors, Emelya begins to suspect his widow. Ageeva had a lover, she was going to divorce her husband...

College teacher Anna Roshchina dies after eating a watermelon. Likhacheva finds a potent poison in a watermelon. Checking the store where it was bought does not give anything: the rest of the watermelons are without poison. The investigation leads the operas to Anna's lover...