A somewhat daffy book editor on a rail trip from Los Angeles to Chicago thinks that he sees a murdered man thrown from the train. When he can find no one who will believe him, he starts doing some investigating of his own. But all that accomplishes is to get the killer after him.

Broadway producer Max Bialystock and his accountant, Leo Bloom plan to make money by charming wealthy old biddies to invest in a production many times over the actual cost, and then put on a sure-fire flop, so nobody will ask for their money back – and what can be a more certain flop than a tasteless musical celebrating Hitler.