At his mother's family house in the south of France, Patrick Melrose has the run of a magical garden. Bravely imaginative and self-sufficient, five-year-old Patrick encounters the volatile lives of adults with care. His father, David, rules with considered cruelty, and Eleanor, his mother, has retreated into drink. They are expecting guests for dinner. But this afternoon is unlike the chain of summer days before, and the shocking events that precede the guests' arrival tear Patrick's world in two.