Essex, 1916. Captain Arthur Hastings, invalided home from the Western Front, is staying at Styles Court when wealthy Emily Inglethorp dies after a violent night-time seizure. Suspicion falls across a household divided by inheritance, an unpopular second marriage and the pressures of wartime life.
Hastings calls on Hercule Poirot, a Belgian refugee living nearby with other displaced countrymen. Poirot reconstructs the movements of medicine, documents and family members, introducing the methodical concern with psychology and exact detail that defines the series. The country-house puzzle is inseparable from the First World War setting that brought both Hastings and Poirot to England.