The narrative centers on a distinguished orchestra conductor named Thibaut. After receiving a diagnosis of leukemia, he embarks on a quest to find a suitable bone marrow donor. During his search, he uncovers the surprising truth that he was adopted and has an elder brother residing in the northern region. His brother works in an office but also performs as a trombonist in a nearby brass band, which faces imminent disbandment. As their worlds begin to intertwine, both brothers grapple with their identities and the possibility of connecting through music and family.