Cristian discovers a relationship between his mother and the representative Livio. Cristian falls ill due to the trauma that the news causes him and his mother decides to leave Livio, concealing from her son that it is a gesture to protect him. Professor Testa is replaced by the holder of the chair, Professor Licitra, who has much stricter methods than the previous teacher. The boys see that, outside of school, the professor gives money to a girl who sells necklaces and they follow her. The girl lives in a family home run by Doctor Guido Cogliati: the professor's son, suffering from AIDS, is hospitalized in the family home.