Hercule Poirot's old friend, mystery novelist Ariadne Oliver, is confronted with a puzzling question about a long-forgotten tragedy: the mysterious deaths of the Ravenscroft couple. Was it a double suicide or a murder-suicide? To solve this cold case, Poirot and Oliver must delve into the past by interviewing elderly witnesses whose memories, like those of elephants, might hold the key. They navigate a labyrinth of conflicting recollections and veiled secrets to uncover the truth behind what happened on that fateful day years ago, proving that some crimes are never truly forgotten.