Ten strangers, apparently with little in common, are lured to an island mansion off the coast of Devon by the mysterious UN Owen. Over dinner, a record begins to play, and the voice of the unseen host accuses each person of hiding a guilty secret. That evening, former reckless driver Tony Marston is found murdered by a deadly dose of cyanide.
The tension escalates as the survivors realise the killer is not only among them but is preparing to strike again . . . and again . . .