It is 1927, and we are in the midst of a riotous bachelor party for the oft-married Jimmy Winter (Sweet and Lowdown). Outside, a trio of bootleggers—Cookie, Billie and Duke—are trying to figure out where to hide the 400 cases of gin they have stashed on their boat. As a stranger approaches, Duke and Cookie rush off. A drunken Jimmy staggers on and comes across the pants-wearing Billie and is immediately smitten. He explains his plight—he must marry someone respectable or his mother will disinherit him, so he’s marrying a woman he doesn’t truly love. Billie isn’t all that interested in his tale of woe, until he reveals that he has a huge Long Island beach house that he never uses, so she swipes his wallet to discover the address. Jimmy assumes Billie is falling for him, but Billie insists that love is for suckers. Jimmy vehemently disagrees (Nice Work If You Can Get It). Jimmy passes out, and Billie reflects on this interesting man unconscious on the ground before her (Nice Work If You Can Get It - reprise). Cookie and Duke rush back on, and Billie tells them that she found a place to store their bootleg—a Long Island beach house! A police whistle pierces the air, and the bootleggers scatter. Senator Max Evergreen and Chief Berry enter, along with Duchess Estonia Dulworth, who has brought along her Vice Squad and vows to rid society of its greatest evil (Demon Rum).
The next morning, Billie, Cookie and Duke have stored their 400 cases of gin into the cellar of Jimmy’s ritzy beach house. Eileen Evergreen, the finest interpreter of modern dance in the world, enters with Jimmy. They were married that morning, and they are on their honeymoon, though Eileen has yet to allow Jimmy to touch her. Cookie, disguised as a butler, enters and they naturally assume he’s their servant. They send him off, and Eileen tells Jimmy that she’s ready for the honeymoon shenanigans to begin—as soon as she takes a bath. She exits into the house as Billie enters, stunned to see Jimmy. Jimmy has no memory of meeting her last night, and as Jimmy flirts with her, Billie confesses that she’s never been kissed. Strictly for educational purposes, Jimmy kisses Billie, and she realizes what she’s been missing (Someone to Watch Over Me).
Four and a half hours later, Eileen is still bathing (Delishous). In the ritzy living room, Cookie and Billie devise a plan for Billie to distract Jimmy from the 400 cases of gin in his cellar. Billie runs off as Jimmy enters, followed by a gaggle of chorus girls who invite him for a group swim, which Jimmy almost accepts (I've Got To Be There). Eileen enters with a flourish, and just as she is about to let Jimmy touch her, he receives a telegram revealing that his last wife refused to sign their annulment, and an irate Eileen storms off to get her father. That night in Jimmy’s ritzy bedroom, Billie breaks in and tries to seduce him, badly (Treat Me Rough). Chief Berry, who has been pursuing Billie, barges in to arrest her. But Jimmy convinces him that Billie is actually his newest wife (Let's Call The Whole Thing Off) and Billie and Jimmy are forced to spend the night together in his bedroom.
The next morning, Jeannie, a happy-go-lucky chorus girl, comes upon Duke, a lug from New Jersey, and mistakes him for an actual English duke. Duke, who is perpetually nervous around women, tries to escape, but Jeannie does everything in her power to get him to notice her (Do It Again).
In the ritzy living room, Jimmy and Billie realize that they are hopelessly in love (S'Wonderful). But Eileen returns with her father—the ultra-conservative Senator Evergreen—and her aunt—the Duchess Estonia Dulworth—to demand that Jimmy and Eileen have a legal wedding. Jimmy has no choice but to marry Eileen, and Billie pretends to be a cockney maid so she can stick around and guard the bootleg. As Eileen beelines towards the cellar to get the wedding china, Jimmy and Cookie frantically distract the wedding party away from the basement (Fascinating Rhythm) as the curtain falls.
On the ritzy terrace, the Vice Squad and Chorus Girls revel (Lady Be Good - instrumental). Billie enters and realizes she’ll never be as happy as the dancing revelers around her (But Not For Me). Cookie and Duke enter and since they’re all now disguised as servants, they plot how they can get the impending wedding luncheon over and done as quickly as possible. The Duchess barrels on to instruct Cookie in the finer points of luncheon preparation. She insists on hiring a string quartet for entertainment, but Cookie has other ideas (By Strauss/Sweet and Lowdown - reprise).
As Billie sets the ritzy luncheon table, Jimmy makes one last attempt to appease her (Do, Do, Do). But Billie will have none of it. As the luncheon begins, Cookie and Duke are frantically serving the luncheon guests, and the Duchess continues to annoy Cookie, who spikes her lemonade with gin. Billie entertains them all with a cockney song (Hangin' Around With You) which mainly serves as an excuse to keep pouring hot soup on Jimmy’s lap. But Billie accidentally pours some steaming soup on Eileen, who immediately fires her. The Duchess, now happily drunk, defends Billie and reveals a deep secret as she grabs onto Cookie, climbs on the luncheon table, and swings from a chandelier (Looking For A Boy). After Cookie drags off the Duchess, an angry Jimmy calls Billie a common criminal, and they realize that they can never be together. Jimmy goes to prepare for his wedding, as Jeannie enters looking for Duke, who Billy accidentally reveals isn’t a real duke. Jeannie is furious, so Duke tries to win her over with a poem (Blah, Blah, Blah). But Jeannie rushes away.
In the ritzy bedroom, Cookie is dressing Jimmy for his wedding as Billie enters to return his wallet. Jimmie and Billie both realize that this is the last time they’ll ever see each other (Will You Remember Me?) but Cookie has this idea…
The Chorus Girls and Vice Squad set up the wedding (I've Got To Be There - reprise). As Senator Evergreen presides, Eileen makes her very grand entrance (I've Got A Crush On You). But just before vows are exchanged, Cookie and Duke rush in, pretending to be Prohibition Agents, though Chief Berry quickly enters and reveals their true identities. As they’re about to be arrested, Jeannie rushes in and proclaims her love for Duke, then the now-sober Duchess proclaims her love for Cookie. Still, Senator Evergreen insists the bootleggers must be arrested, but Jimmy’s mother, Millicent, makes an appearance, revealing the true nature of her son’s heritage—Senator Evergreen is Jimmy’s father. The Senator proclaims the day a joyous one and all are free to pursue their new and surprising loves. Jimmy realizes that Billie has rushed to the boathouse to sail away forever, and he rushes to swear his devotion to her. Millicent follows and reveals that she happens to be the biggest rum runner on Long Island, and she’d like Billie to marry her son and take over her business. Billie happily accepts (Someone To Watch Over Me - reprise). And on the ritzy terrace under a starry night, love has blossomed, the bootleg is opened and the company celebrates their new-found joy (They All Laughed!).