Shy milkman Burleigh Sullivan accidentally knocks out drunken Speed McFarlane, a champion boxer who was flirting with Burleigh's sister. The newspapers get hold of the story and photographers even catch Burleigh knock out Speed again. Speed's crooked manager decides to turn Burleigh into a fighter. Burleigh doesn't realize that all of his opponents have been asked to take a dive. Thinking he really is a great fighter, Burleigh develops a swelled head which puts a crimp in his relationship with pretty nightclub singer Polly Pringle. He may finally get his comeuppance when he challenges Speed for the title.

Boisterous nightclub entertainer Buzzy Bellew was the witness to a murder committed by gangster Ten Grand Jackson. One night, two of Jackson's thugs kill Buzzy and dump his body in the lake at Prospect Park in Brooklyn. Buzzy comes back as a ghost and summons his bookworm twin, Edwin Dingle, to Prospect Park so that he can help the police nail Jackson.

John Lobert runs a training camp in Florida for the New York Giants. Every year, he evaluates the 18-22 year old hopefuls to pick the best for a minor league contract.

Song-and-dance man Bert Kalmar can't continue his stage career after an injury, so he has to earn his money as a lyricist. By chance, he meets composer Harry Ruby and their first song is a hit. Ruby gets Kalmar to marry his former partner Jessie Brown, and Kalmar and Jessie prevent Ruby from getting married to the wrong girls. But due to the fact that Ruby has caused a backer's withdrawal for a Kalmar play, they end their professional relationship.

Washington hostess Sally Adams becomes a Truman-era US ambassador to a European grand duchy.

The Marx Brothers help young Broadway hopefuls when they get mixed up with gangsters due to a tin of sardines containing Romanoff diamonds.