It is a historical mystery set in England between World War I and World War II. The story revolves around the aristocratic Hartford family, their grand estate Riverton, a mysterious death, and the secrets that surround it. The novel is narrated by Grace Bradley, a 98-year-old former housemaid at Riverton, as she recounts her memories of the summer of 1924, when a young poet committed suicide at a party held at the estate. The only witnesses were the Hartford sisters, Hannah and Emmeline, who never spoke to each other again after the incident.