The plot involves the widely successful orchestra conductor Pierre Morhange, who returns to France when his mother dies. He reminisces about his childhood inspirations when he and his former classmate read the diary of their old music teacher Clément Mathieu .The story goes back to 1949 when a young Morhange is the badly behaved son of single mother Violette. He attends the boarding institution for “difficult” boys, presided over by a strict headmaster. The new teacher brightens up the school and assembles a choir, leading to the discovery of Morhange’s musical and physical talents and a transformation in the children.