"The Brass Band" is a story that follows the life of the famous orchestra conductor, Thibaut. When he receives a diagnosis of Leukemia, he embarks on a journey to find a suitable donor for a bone marrow transplant. Along the way, he uncovers the shocking truth that he is adopted and has an older brother living in the North. This brother, an office worker by day, also plays the trombone in a local brass band that is on the verge of disbanding. As they come together against the backdrop of the impending closure of the only factory in the area, their reunion sparks a unique and heartwarming tale of brotherhood, community, and the power of music.