At the age of three, little Wolfgang has lost his parents. Since then his uncle Eduard raises the boy. As a former concertmaster Eduard has recognized how gifted his nephew is and the boy learns the hard way. The 6-year-old must practice daily 6 hours at the piano and already impresses at famous music parties. When Eduard Fabricius breaks a leg after a concert in Lucerne and must go to the hospital, he can be persuaded by a paediatrician to grant some carefree vacation weeks in a manor for Wolfgang. The manor belongs to the young widow Elisabeth who soon grows very fond of the little boy. Wolfgang makes friends with 11-year-old Heidi and Jöggi, a boy his age who first saw a rival in him. When Wolfgang saves a young dog from a mountain stream, however, he gets pneumonia, and Elisabeth worries about him. But when he recovers, his uncle fetches him. A strenuous concert tour begins. One day at the piano the boy breaks down.