Deborah (Carroll Baker) and Marcel (Jean Sorel) return to Geneva from their honeymoon in Europe. Marcel learns of his former fiancee Susan's suicide, and is confronted by a man named Philip (Luigi Pistilli) who accuses him of murdering her. Marcel begins to receive threats from someone who holds him responsible for Susan's death. His new bride Deborah also becomes the target of these threats, and a weird neighbor named Robert with voyeuristic tendencies (George Hilton) begins fixating on her as well.