In 1935, reporter Dave Hoffman visits the Happy Club to reminisce with owner Gino Lupo about the good old days of prohibition. Gino recalls a waterfront meeting in 1927 between Al “The Musician” Fusary, a Chicago hired killer and Max Lassiter, the second in command to gangster Big Dan Hennessy: During the meeting, the power hungry Max hires Al to eliminate his boss. Later, at the Happy Club, Big Dan, the club’s owner, lavishes expensive gifts on showgirl Rosemary Lebeau because he and Rosemary were both reared in the same orphanage. Rosemary is engaged to police sergeant Jimmy Murphy, however, and is therefore immune to the gangster’s blandishments. That night, when Big Dan leaves the club, he is gunned down by Al. Gravely wounded, Big Dan suspects that Max is behind the shooting and so summons his attorney, George Eagle, to his hospital room. There, Big Dan, an inveterate prankster, laughs so hard after bequeathing his entire estate to Rosemary that he laughs himself to death. At Big Dan’s wake, George reads the will which stipulates that the orphanage will inherit the estate if anything happens to Rosemary. As Rosemary surveys her new empire with girlish glee, Max simmers with resentment until Billy Boy Barnes, one of his underlings, suggests that Max marry Rosemary to gain control of Big Dan’s holdings. When Jimmy asks Rosemary to relinquish her newfound notoriety as “Queen of the Underworld,” she refuses and they argue. Soon after, Max comes courting but Rosemary rebuffs his advances. Upon discovering that she owns speakeasies and gambling halls, Rosemary decides to close all the illegal operations and retain only the Happy Club, a legitimate organization. When Rosemary launches a search for a new dancing partner to perform the tango with her, Max instructs Dominic Rodriguez, one his subordinates, to audition for the role. After Rosemary and Dominic perform a torrid tango, Jimmy, jealous of their onstage ardor, comes to Rosemary’s dressing room and provokes an argument with her. After Jimmy angrily departs, Dominic invites Rosemary to dinner, but when he takes her home, he makes unwelcome advances and she knocks him unconscious. Soon after, Jimmy comes to the apartment, shows Rosemary a wanted poster for Dominic and then arrests him. When Rosemary informs Jimmy that she has closed all her illicit enterprises, he agrees to marry her. Afterward, Max’s thugs forcibly deliver George to Max’s headquarters, where Max threatens the attorney with a cement suit for writing Big Dan’s will. George then volunteers to circumvent the will, explaining that he bought the orphanage and thus is a beneficiary of Big Dan’s bequest. George agrees to transfer the orphanage’s mortgage to Max for a percentage of the business, thus allowing him to reopen all the illicit operations. Rosemary is waiting at the church for Jimmy on her wedding day when Jimmy storms up the stairs and informs her that all the gambling halls have been reopened. Furious at Jimmy for assuming that she has lied to him, Rosemary jumps into the car waiting to take them on their honeymoon and is kidnapped by Max. Upon discovering that Rosemary has been abducted, Jimmy and Gino speed after Max, whose car runs out of gas in front of the Happy Club. Taking cover in the club, Max and his thugs hold off Jimmy at gunpoint. Just then, an unseen figure flashes a spotlight in Max’s face, blinding him and rendering him defenseless. After Max’s arrest, Rosemary awards the club to Gino, takes over the orphanage and marries Jimmy. His thoughts returning to the present, Dave speculates that perhaps Big Dan is still alive, having faked his death to escape the rackets, and that he may be the mystery man who turned the spotlight on Max.