After the death of his Russian mother, nine-year-old orphan Peter lives with Professor Hartmann and his daughter Helga, who cares for him like a mother. Peter is very musical. He especially loves the melancholy songs of the Don Cossack Choir, which remind him of his mother. Because the boy has suffered from a severe heart defect since birth, his doctor, Dr. Stark, has forbidden him any excitement, including music. When one day the Don Cossack Choir's tour bus breaks down near Peter's house with engine trouble, the little boy meets the conductor Serge Jaroff and his famous singers in person.
as Rolf Bender
as Professor Hartmann
as Helga, seine Tochter
as Peter
as Chefarzt Dr. Burger
as Dr. Heinz Stark
as Himself
as Elisabeth
as Karl
as Anneliese
as Mutter
