Captain Arthur Hastings receives a telegram from an old friend, Zoe Havering, informing him of the murder of her uncle-in-law, Harrington Pace. Under normal circumstances, Hastings would call upon the expertise of Hercule Poirot, the world's greatest detective, to handle the case. However, Poirot has been sidelined by a bout of influenza, leaving the sleuthing up to Hastings, who normally only chronicles and catalogs Poirot's cases. Hastings, a soldier, not a detective, is faced with a secluded hunting lodge full of suspects and only the faintest idea of what to do.