In the French countryside in 1949, the musician Clement (Gerard Junior) went to a boys' boarding school nicknamed "Tang Di" as an assistant teacher. Most of the students in the school are difficult problem children, corporal punishment is common here, and the school principal (François Belleion) only cares about his own future and is cruel and oppressive. Clement, who has a calm personality, tries to improve this situation in his own way. He re-creates musical works, organizes a choir, and decides to use music to open the closed hearts of students. However, things are not going well. Clement discovers that the student Pierre Moanche (Jean-Baptiste Monnier) has an extraordinary musical talent, but he grew up in a single-parent family and has an extremely sensitive and withdrawn personality. How to release Pierre's musical talent gives Clement a headache; at the same time, his relationship with Pierre's mother gradually becomes subtle.