During the twenty years school reunion classmates suddenly learn that one of them - Nadezhda Kruglova - is a proud mother of ten children.

Little boy Stepan loved listening to fairy tales his mother made up before bedtime. One day, she told him about the river near where they lived. It was a large and mighty river, but it needed human protection and care. In the morning, his mother couldn't find Stepan — he had gone to look for the source of the river. Thus began Stepa's adventures.

The film raises environmental issues and examines the nature of the relationship between the manager and the team.

A life of eight-grader suddenly changes after he is officially declared genius in his school.