A mediocre stand-up comic with gambling debts runs away to the West Side of Chicago, and under an assumed name, takes a job as a janitor. Yearning to go back on the stage and win applause at all costs, he contacts his agent, who books him a gig to perform.

Often described as a French New Wave film made in Hollywood, Arthur Penn's 1965 art movie enters the unsettlingly paranoid world of a nightclub comic on the run from the Mob. Having fooled around with the wrong blonde and gambled himself into an unpayable debt, an entertainer (Warren Beatty) flees to Chicago, where he hides out and changes his name to Mickey One. He hooks up with Jenny (Alexandra Stewart) and Castle (Hurd Hatfield), the owner of the nightclub Xanadu, but he cannot shake the paralyzing conviction that he's being pursued no matter where he is. After being beaten by unknown assailants, Mickey finally decides that escape is impossible, so he might as well just do his thing.