Hino Kahoko is a student whose school is divided into two branches—the Normal Branch, in which students wear grey uniforms, and the Music Branch, in which the students wear white. The school's tradition is a music competition, but it is more common that students from the Music Branch are chosen to compete. Kahoko is surprised one day to encounter a fairy named Lili. Solely because she is the only student to see him, she is the only student from the Normal Branch to be in the competition.

Kahoko doesn't have any musical knowledge, until Lili grants her a magic violin, one that anyone can play if they believe they can truly do it. Kahoko must now face the trials of the competition, her competitors, and her peers.