When he takes a job teaching music at a school for troubled boys, Clement Mathieu is unprepared for its harsh discipline and depressing atmosphere. But with passion and unconventional teaching methods, he's able to spark his students' interest in music and bring them a newfound joy. However, it also puts him at odds with the school's overbearing headmaster, locking Mathieu in a battle between politics and the determination to change his pupils' lives.