Black comedy starring Diane Keaton and Woody Allen. When Carol Lipton (Keaton) hears about the sudden death of her neighbour, Lillian (Lynn Cohen), she immediately suspects foul play as Lillian's husband Paul (Jerry Adler) appears too happy to her. As Carol comes up with theories about what might have happened, she begins to spy on Paul and reluctantly gets her husband, Larry (Allen), involved in helping her solve the mystery.