Eight-grader Petya Kopeikin, despite his short stature and nondescript appearance, is constantly in the spotlight. Petya is noble, witty, well versed in literature, he writes wonderful poems. Kopeikin has long been secretly in love with his classmate Masha Goroshkina, and she is passionate about the new student from 9 "A" Kolya Kristallov. Masha tells Petya about her feelings and asks him to hand over a note to Kolya. Deeply worried from unrequited love, Petya not only doesn't stand in the way of a happier rival, but even helps him win Masha's heart. He wants to prove that courage and honor were not only inherent in the times of “musketeer” novels, but exist in our time. Petya chooses to follow the example of the hero of the famous play Edmond Rostan and in his actions copies Cyrano de Bergerac.

Two completely different sons grow up in the same family. The youngest, Frol Kalitkin, is an exemplary seventh-grader, winner of Olympiads, the first student. And the eldest, Andryusha, is a loafer, a loafer and a dude. The “correct” Frol takes up the upbringing of his brother.