A serial strangler is on the loose, and a mob of neighborhood vigilantes is on the hunt. When several neighbors wake up the skittish Max Kleinman (Woody Allen), a bookkeeper, they want him to get dressed and join the search party. Finally pulling himself together, Kleinman goes downstairs to find no one waiting for him. Left to investigate alone, he winds up in one predicament after another, which eventually leads him to meet Irmy (Mia Farrow), a sword swallower from the visiting circus.