Ariadne Oliver enlists Hercule Poirot to investigate a decades-old murder-suicide that continues to disturb her peace of mind. The novelist seeks to uncover the truth behind the deaths of the Ravenscrofts, a couple whose demise remains shrouded in ambiguity despite the presence of their fingerprints on the fatal weapon. Poirot, despite his advanced age, applies his methodical intellect to the cold case, navigating the fallibility of human memory and the secrets of the past. The narrative unfolds through a blend of investigative dialogue and psychological probing, as the duo attempts to reconstruct events that occurred twelve years prior.

This novel is often noted for its meta-fictional elements, as it features a mystery novelist character who mirrors the author's own experiences. The narrative is frequently analyzed for its exploration of aging and the persistence of past trauma within the framework of a traditional whodunit. While some readers find the pacing slower than earlier works in the series, the intricate puzzle-solving remains a central draw for fans of the genre. The book serves as a late-career reflection on the nature of crime and the way history echoes through the lives of those left behind.