The story is set in 1990s South London and follows a 15-year-old girl named Mary. On a school trip, Mary drinks an entire bottle of alcohol very quickly on the bus ride home and loses consciousness. She is discovered by a teacher and taken to the hospital. There, a nurse learns that Mary was worried about her sick grandfather and felt neglected by her parents, which led her to drink. Her parents talk to her at the hospital, promise to listen to her, and they all go home feeling better.