On a hot day in 1935, at her family's country house, thirteen-year-old Briony Tallis, who means to be a writer, sees something pass between her older sister Cecilia and Robbie Turner, the housekeeper's son, that she does not understand. That night she accuses Robbie of a crime, and the novel follows what comes of it through the retreat to Dunkirk and the wards of wartime London.