|Groucho Marx||Otis P. Driftwood|
|Kitty Carlisle||Rosa Castaldi|
|Margaret Dumont||Mrs. Claypool|
|Allan Jones||Ricardo Baroni|
|Walter Woolf King||Rodolfo Lassparri|
|Sig Ruman||Herbert Gottlieb|
The Marx Brothers run amuck in the world of opera when Otis B. Driftwood meets aspiring singer Ricardo, who is determined to win the love of fellow performer Rosa . Aided by Fiorello and Tomasso, Otis attempts to unite the young couple, but faces opposition from the preening star Lassparri, who also has his sights on Rosa. Traveling from Italy to New York, Otis and friends rally to try and win the day.