Professor Rodolfo Calabrone, the headmaster of a high school, who despite his gruff appearance is a good man who looks after his son and cares for the welfare of the students and the school itself. Professor Calabrone is often the victim of students' pranks, Professor Beccafico's clumsiness and Professor Zappa's obsessive jealousy.
The story becomes complicated when Angela, the daughter of a rich industrialist, enrols at the school under a false name. Angela meets Carlo, a playboy student, but Carlo's father forbids her to date him so as not to jeopardise her relationship with the rich industrialist, Pastorelli.
Angela, instigated by her companion Lisetta, starts to make the headmaster Calabrone believe she is in love with him as a joke. The headmaster falls in love with Angela and introduces her to his son, even writing a letter of employment to the girl's father.
When Angela and Carlo clarify their feelings and really fall in love, the headmaster catches them in an intimate moment and realises he has been the victim of a cruel joke. However, Angela regrets her actions and manages to make it up to Professor Hornet, leading to the story's conclusion with a marriage between Professor Zappa and Professor Beccafico.
The plot explores themes of deceit, jealousy and forgiveness, with a happy ending that restores harmony between the characters.