The story of the premiere of The Cradle Will Rock, at the Venice Theater on June 16, 1937, is as dramatic as the show itself. Locked out of the WPA Theater by government troops, an impromptu performance without sets or costumes took place in a hastily hired theater, with actors and musicians performing from the audience and Blitzstein narrating at the piano. In 1939, a young Leonard Bernstein led a revival at Harvard in which he narrated from the piano just as Blitzstein had done.
Moll, a prostitute, is thrown into Steeltown Jail for refusing a police officer. At the jail, she meets Harry Druggist, in jail for vagrancy. Because of a mistake by a police officer, the Liberty Committee are brought in; they are a group of prominent citizens formed by Mister Mister, boss of Steeltown, to oppose the union. Harry the Druggist tells Moll that the Liberty Committee are bigger prostitutes than she is; one by one he tells her how each of them, and he himself, sold out to Mister Mister.
As this is happening, Larry Foreman, a union agitator, is thrown into the jail for "inciting to riot" after having been beaten by the police. We learn how Mister Mister has tried to subvert his activities; finally, Mister Mister himself arrives to release the Liberty Committee. He offers to buy out Larry Foreman and offers him a place on the Liberty Committee. Foreman refuses, and everyone hears the music of the union meeting outside, organizing to oppose Mister Mister.