After graduation, Nadia Kulagina comes to work in a school where she once studied. After her appearance, the most hopeless student Dimka Lopatin, who was even wanted to be expelled from school, becomes one of the best students and a faithful friend of the new class teacher.

A young sportsman Grisha Fokin falls in love with Masha, the wife of an outstanding scientist - Yuliyan Nikolayevich Stepanov.