Hello River!(1979)

Original title: Здравствуй, река!

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.