Woody Allen plays the nebbish clerk Kleinman (in a throwback to his characters from Sleeper and Love and Death), who is awakened in the middle of the night by a vigilante group who want him to help capture a serial killer on the loose.
Kleinman reluctantly agrees, but when he gets to the street, the vigilantes are gone and Kleinmen spends most of the film wandering the shadowy back alleys in search of the citizen's brigade. Meanwhile, a circus is in town.
When sword-swallower Irmy (Mia Farrow) catches her creepy clown husband (John Malkovich) getting familiar with trapeze artist Marie (Madonna), she packs her bags and heads for town, where she meets up with Kleinman.
This meeting sets up a number of plot lines that has Irmy befriending a trio of prostitutes (Jodie Foster, Lily Tomlin and Kathy Bates) at the local brothel and accepting $700 from a university student (John Cusack) who wants to sleep with her.
She finally meets up with her husband, and they then find an abandoned baby which they decide to raise as their own.