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. Eduard Fabricius recognizes that he has demanded too much of his nephew, and finally makes up his mind.