Jimmy Durante stars as Knobby Walsh, the opportunistic trainer of boxing contender Joe Palooka (Stuart Erwin). Joe manages to knock out the champ (William Cagney) and wins his girlfriend in the process. But now that he's the champ, can Joe survive life in the fast lane? Director Benjamin Stoloff pulls together a vibrant cast, including Robert Armstrong (King Kong) and a trio of lovely actresses, Thelma Todd, Mary Carlisle, and the Mexican Spitfire herself, Lupe Velez!