For all her prolificacy, Agatha Christie relied too often on one particular plot twist, and as soon as you recognize her old favorite here, the film loses all interest—it has nothing going for it apart from the mystery, which, of course, is no way to make a mystery movie. Guy Hamilton’s direction is unbelievably slack and monotonous, and his handling of the aging stars—Angela Lansbury (who seems to be wearing one of Boris Karloff’s old foreheads), Elizabeth Taylor, Rock Hudson, Kim Novak, Tony Curtis—suggests Paul Morrissey on a hung over morning.