Based on the hit play by Ben Hecht and Charles MacArthur, a reporter wants to leave town and get married, but he is enticed by a hot story of an escaped murderer.
While reporters wait for the hanging of Earl Williams, editor Walter Burns (Adolphe Menjou) has men looking for reporter Hildy Johnson (Pat O'Brien), who gets a marriage license with Peggy Grant (Mary Brian) and plans to go to New York. Walter pulls a fire alarm and gives Hildy four drinks. Hildy goes to the press room and says he is going into advertising, showing $500 from Peggy's parents. The mayor and sheriff (Clarence Wilson) can gain politically by executing a red who killed a colored policeman, "reforming the red menace with a rope." Roy Bensinger (Edward Everett Horton) reports Williams is being examined by a psychiatrist, while mentioning who provided his last meal. Molly Malloy (Mae Clarke) tells reporters how she took in Williams for one night after he lost his job. The sheriff gives out tickets for the hanging.
To re-enact the crime the professor gives the sheriff's gun to Williams and gets shot. As Williams escapes, Hildy calls Walter and is on the job, asking for the $260 he paid Jacobi to get the story. Peggy asks for the money, but Hildy gives her the tickets and promises to meet her. A messenger brings the governor's reprieve of Williams to the mayor and sheriff, but they send him away. Louie gives Hildy $150. Williams comes in the window and tells Hildy he is an anarchist, not a Bolshevik, fainting. Hildy calls Walter and gets a call from Peggy. Molly comes in, and Williams tells her he is ready to die and that she is good. Hildy puts Williams in Bensinger's roll-top desk. The reporters come in, but Hildy sends Bensinger out for a throat remedy. Peggy's mother comes in and says Hildy has Williams. Molly says she knows where he is; she is pressed and jumps out the window. Walter finds out from Hildy where Williams is and has Peggy's mother taken away by Louie. Walter tells Hildy they will knock out Chicago's administration, and Hildy writes the story. Peggy comes in and says Hildy lied, then leaves. Bensinger comes back, but Walter offers him a job with a raise and sends him out, canceling the deal. Hildy regrets Peggy, and Walter discusses women.
Reporters return with the sheriff, who questions Hildy. Walter gives the sheriff his gun. Peggy's mother returns and accuses Walter of kidnapping. Williams taps on the desk and is captured as reporters call in the story. The proud mayor and sheriff arrest Hildy and Walter for aiding a criminal; but the messenger returns with Williams' reprieve and says he was bribed. Walter gloats over the "hidden power of the press," as he and Hildy are released. As Walter and Hildy say good-bye and reminisce, Walter gives him his watch. Hildy and Peggy leave for New York, but Walter makes a call to have Hildy arrested for stealing his watch.
This story portrays the alluring, wise-cracking, mob mentality of the modern press corps. The excitement is so addicting that Hildy has a hard time leaving it even for a great woman, who is everything he wants. The anarchist is a political pawn, and the corruption of big-city politics is apparent.