Roxy Robinson, one of the men working for Fat Sam, is rubbed out by men working for Dandy Dan. At Sam's Grand Slam speakeasy, Blousey, a budding singer, come for an audition, but Sam is too worried about Dan. Fizzy the janitor tells her not to worry, as he has been waiting for his promised audition for months now. Blousey meets Bugsy when he trips over her luggage. He is immediately taken with her, but she resists his advances. The speakeasy is attacked by Dan's men, who fire their 'splurge' guns and then escape.

Bugsy offers to take Blousey home, even though he has no money for a cab. They stop at a café, where he tells her that he makes his living by finding potential boxers. When it's time to pay the bill, Bugsy traps the waitress in a phone booth and makes a quick exit with Blousey.

After the speakeasy has closed, Sam and his moll, Tallulah, leave. One of the chorus girls stays behind and dances while Fizzy sings about his desire to become a performer. Blousey gets an audition when Lena, the star of a Broadway show, becomes indisposed. Blousey seems certain to get the job, but then Lena returns to the show. Blousey is furious and argues with Bugsy, frustrated after months of trying to get ahead as a singer. Bugsy calms her down and tells her that he knows Sam and will try and arrange another audition.

Dan's men continue to attack Sam's men, but during a restaurant shooting, Doodle drops his Splurge gun. Dan complements his men for their successes but is angry at Doodle for his mistake. Dan and his men back Doodle into a corner and throw custard pies at him. Sam receives a tip-off about the Splurge guns and dispatches all his men except Knuckles to see if then can get their hands on one. The men arrive at a Chinese laundry but it is a trap, and they are all shot by Dan and his men. Bugsy goes to the Grand Slam to get Blousey an audition. He is met by Tallulah, who has a crush on him. He refuses her advances, but when she sees Blousey arrive, she kisses him to make her jealous. Sam hires Blousey and decided to call in Looney Bergonzi to help get rid of Dan.

Bugsy goes backstage to try and patch things up with Blousey, but she rejects him. Sam sees him and hires him to go to a meeting with Dan. Sam also takes Looney along to trap Dan, but they are completely outnumbered and outgunned. Looney is quickly covered in custard pies, so Bugsy distracts Dan's men and then manages to help Sam make a getaway. Sam lends him his car as a reward and pays him $200. Bugsy rings Blousey with the good news and takes her out for a romantic picnic and a boat ride on the lake. When they get back to the city, he tells her that he has enough money left to buy them a ticket each to Hollywood.

Bugsy returns Sam's car to the garage and is attacked and robbed. He is saved by Leroy, who Bugsy realises could be a great boxer. He takes him to the gym and trains him to be a fighter. Dan's men continue to wreck Sam's business, so he sends Tallulah to get Bugsy. He pays him $400 to help him get rid of Dan. When Bugsy phones to tell Blousey that they will have to delay their trip to Hollywood, she gets angry with him and hangs up. Bugsy and Leroy follow Dan's men and find where the splurge guns are being held. The place is heavily guarded however, so Bugsy hires men from a local soup kitchen. They trap the guards in a warehouse and take the guns to Sam.

Dan attacks the club, but Sam's men retaliate with the splurge guns and soon everyone is covered in custard. Razamataz strikes a note on his piano and hostilities cease and everyone breaks into a conciliatory song. Bugsy and Blousey are re-united and leave for Hollywood.