When a wealthy man dies in a wartime bombing, his young widow inherits a fortune, triggering a complex investigation into her past and the validity of her marriage. Hercule Poirot is drawn into the case by a suspicious sister-in-law who claims to have received warnings from the spirit world regarding the widow's first husband. The detective must navigate a web of family secrets, greed, and deception to uncover the truth behind the inheritance. The narrative follows a traditional third-person perspective, focusing on Poirot's methodical gathering of clues and psychological observation of the suspects.

This novel is widely regarded as a quintessential example of Christie's ability to weave complex social commentary into a traditional detective framework. Readers often highlight the clever use of the wartime setting to heighten the sense of instability and moral ambiguity surrounding the characters. The mystery is frequently praised for its intricate construction and the way it challenges the reader's assumptions about the widow's true identity. Critics and fans alike note that Poirot's involvement provides a steady, analytical anchor amidst the chaotic backdrop of the Blitz. The book remains a staple for those interested in the evolution of the golden age detective story.