The story revolves around the students of the ninth grade, who have always been known for their exemplary behavior and high academic performance. Everything changed after their homeroom teacher, Anatoly Germanovich Nosov, fell ill. After his unexpected departure, the ninth graders were left without a strong guiding hand. The legend of their discipline was shattered. Nosov's granddaughter, Anya, turns out to be the most difficult child in the school. And the newcomer, Ilya Epifanov, creates situations in which the children do not show themselves in the best light...