W. A. Mozart's childhood was very busy, connected with constant travelling, full of fame and admiration. His father Leopold, an accomplished musician, led his son purposefully towards the role of child prodigy. However, their travels in Europe were not only associated with success, but also with the family's struggle for subsistence and the mother's eternal fear for the fragile health of her children. And so we follow Mozart's first steps in the world of music to the premiere of his first opera, La finta semplice, which he wrote at the age of twelve.

A young and sympathetic teacher joins the music school. He leads the school orchestra and also teaches twelve-year-old Anezka to play the cello. The girl falls in love with him and only her grandmother, who lives alone and does not get along with Anezka's mother, her daughter-in-law, has any sympathy for her. But even she can't help Anezka overcome her first emotional turmoil, so the girl uses a little trickery to get closer to her teacher...