"What I intend to say to you will come as a shock..."

With these words, Lady Athelinda Playford --- one of the world's most beloved children's authors --- springs a surprise on the lawyer entrusted with her will. As guests arrive for a party at her Irish mansion, Lady Playford has decided to cut off her two children without a penny...and leave her vast fortune to someone else: an invalid who has only weeks to live.

Among Lady Playford's visitors are two strangers: the famous Belgian detective Hercule Poirot, and Inspector Edward Catchpool of Scotland Yard. Neither knows why he has been invited --- until Poirot begins to wonder if Lady Playford expects a murder. But why does she seem so determined to provoke a killer? And why --- when the crime is committed despite Poirot's best efforts to stop it --- does the identity of the victim make no sense at all?