During a long, hot summer in seventies London, young neighbors Holly and Marina make a childhood pact to be friends forever. For the troubled, unpredictable Marina, Holly remains the only constant in her life. Meanwhile, Holly buries herself in her books out of frustration. She holds just one secret: her increasing passion for Marina’s brother. The bond between the young women grows through the years as they share all the pleasures and pain that life has to offer, including sex, love, and rock ‘n roll. For Holly, however, a friendship that has never been equal gradually begins to feel like a trap.