Ten strangers, each harboring a dark secret, are invited to a remote island off the Devon coast by an unknown host, Mr. and Mrs. Owen. Upon arrival, they are greeted by the butler and housekeeper, Thomas and Ethel Rogers, who claim their hosts are delayed. After dinner, a gramophone record plays, accusing each guest of a murder they committed but never faced justice for. The first guest, Anthony Marston, dies instantly from cyanide poisoning.