ABC contre Hercule Poirot

Albert Aachen, a clown with a unique diving act, is found dead, the murder weapon happens to be a poison dart. When a woman named Betty Barnard (Grazina Frame) becomes the next victim, detective Hercule Poirot (Tony Randall) suspects that Sir Carmichael Clarke (Cyril Luckham) could be in grave danger. As Poirot and Captain Hastings (Robert Morley) look into the crimes, a beautiful woman with an interesting monogram named Amanda Beatrice Cross (Anita Ekberg) becomes the focus of their investigation, at least until she leaps into the Thames.