The Sixties in the suburbs of Paris.
Hannah is sixteen years old, has two pretty sisters and parents who love her. But she's unhappy. Gifted with musical talent, she has chosen an instrument that resembles her, the bass, and dreams of joining her school's jazz band.
She passes the audition with flying colors, but her new colleagues, keen to maintain the group's male line-up, stop at nothing in their efforts to discourage her...