At a literary luncheon, crime novelist Ariadne Oliver is cornered by an overbearing stranger, Mrs Burton-Cox, who demands to know the truth about a death that happened long ago. Years earlier, Oliver's school friend Margaret Ravenscroft and her husband, retired General Alistair Ravenscroft, were found shot together on a clifftop near their home, a single revolver lying between them. The inquest could never settle whether the couple died by a suicide pact or whether one of them killed the other before turning the gun on themselves. Now Mrs Burton-Cox's son is engaged to the Ravenscrofts' daughter, Celia, who is also Oliver's goddaughter, and the unanswered question has resurfaced. Unsettled and curious, Oliver turns to her old friend Hercule Poirot. Together they set out to reconstruct events that everyone else has tried to forget, seeking out the aging witnesses Oliver calls her elephants, people whose memories may still hold fragments of what once happened. From scattered recollections of governesses, neighbours, household staff and a retired police officer, a picture slowly assembles, complicated by half-truths, faded gossip and the unreliable nature of memory itself. Poirot weighs the contradictions with patience while Oliver pursues the human threads, and the long-buried story of the marriage edges back into the light. The investigation becomes a study of how the past lingers, how people remember what they want to remember, and how a quiet domestic tragedy can keep its secret for decades.