An American movie actress, best known for playing dumb blondes, is Scotland Yard's prime suspect when her husband, Lord Edgware, is murdered. The great detective, Hercule Poirot, digs deeper into the case.

Hercule Poirot (Sir Peter Ustinov) appears on a television talk show with actor Bryan Martin (Lee Horsley), who is making an action detective movie with Jane Wilkinson (Faye Dunaway). He also meets impressionist Carlotta Adams (Faye Dunaway). They all go to a party and Jane asks him and Captain Arthur Hastings (Jonathan Cecil) to go and meet her husband, Lord Edgware (John Barron) in regards to a divorce. They do so, to discover that the Lord had already granted her a divorce. Jane is delighted, but drops hints that she could have killed the Lord if he didn't grant her the divorce. The next day, Lord Edgware is found dead, and all of the staff at the Lord's house swear that Jane was the one who did it, but witnesses at another Lord's party swear that Jane was with them. Carlotta then dies, and Poirot must investigate, as Inspector Japp (David Suchet) is determined to put Jane away.—Lee Horton <[email protected]>