Thibaut Désormeaux, one of the most successful orchestra conductors of his generation, is hoping his sister is a compatible bone marrow donor to treat a rapidly progressing leukemia. At the sight of the DNA results and after confronting his mother, not only does he discover that he was adopted, but also that he has a younger brother, Jimmy, also adopted, but by a modest family. Employee in a school canteen, Jimmy plays in the local marching band and even seems to have a talent out of the ordinary. While in remission, Thibaut decides to give Jimmy the chance he never had to nurture his gift and help the village band to win a national contest.