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... see more