Charlotte Castang is a working-class 13-year-old girl, who lives in a drab, run-down neighbourhood, and is ready to become an adult. Her mother died giving birth to her, and she lives with her crass brother and a father whose attention is elsewhere. Her only friend is Lulu, a sick 10-year-old she regards as a pest. Charlotte is antisocial, bored and dreams of a better life. Her life improves when she meets Clara Bauman, a pianist prodigy.