Backstage at the Zangler Theatre in New York in the 1930s, the Zangler Follies wraps its final performance for the season. Tess, the dance director, guides the dancers through their chorus call. Bobby Child, the rich son of a banking family, auditions for Mr. Zangler ("K-ra-zy for You") but ruins his chances by stepping on Zangler's foot. Dejected, Bobby runs into his disapproving mother and his wealthy long-time fiancée, Irene. Bobby's mother demands that he travel to Deadrock, Nevada, to foreclose on a rundown theatre. As the women argue over him, Bobby imagines himself dancing with the Follies Girls ("I Can't Be Bothered Now"). Brought back to reality, he decides to escape to Nevada.
Meanwhile, life is slow in Deadrock, a sleepy gold-mining town full of dawdling cowboys ("Bidin' My Time"). Polly Baker, owner of Deadrock’s Gaiety Theatre, receives a notice of foreclosure from New York, signed by “Bobby Child.” She vows to get even with this Bobby Child, if she ever meets him. Lank Hawkins, proprietor of the town's saloon, urges Polly to marry him and let him buy the theatre before the bank takes it. But Polly refuses on both counts.
Bobby enters Deadrock, exhausted and nearly dying of thirst, but he takes one look at Polly and suddenly "Things Are Looking Up." Bobby finds himself in quite a bind: if he forecloses on the theatre, he’ll lose the girl of his dreams. He suggests they put on a show to pay off the mortgage. Polly agrees to this plan, until she finds out who he is and suspects a trick. Bobby and Polly are both heartbroken, but Bobby decides to put on the show anyway... disguised as Mr. Zangler.
A few days later, several Zangler Follies girls arrive in Deadrock ("Girls Enter Nevada"). Bobby, disguised as Zangler, plans to lead them in a spectacular show at the Gaiety. Polly is quickly smitten by this new "Mr. Zangler" ("Someone To Watch Over Me").
Rehearsal for the show is disastrous; the cowboys are terrible dancers."Zangler" and the girls masterfully inspire them ("Slap That Bass"), and the show is soon back on track. Irene arrives unexpectedly, however, and threatens to expose Bobby's charade. Meanwhile, Polly has fallen desperately in love with the man she believes is Bela Zangler ("Embraceable You").
On opening night, everyone is in high hopes ("Tonight's the Night!"). But the only people to attend are Eugene and Patricia Fodor, British tourists writing a guidebook on the American West. Despite the disappointment, everyone realises that the show has revitalised their once-sleepy town, and they celebrate with a spirited rendition of "I Got Rhythm."
Bobby tries to confess his deception to Polly, but the real Bela Zangler enters, exhausted and parched. Polly sees the two Zanglers and realises what has happened. She slaps Bobby and leaves in a huff. Irene insists that Bobby return to New York with her, but Bobby rejects her, affirms his love for Polly, and exits. Shocked and hurt, Irene turns to Lank and says, "You are, without a doubt, the rudest, most uncouth, roughest man I have ever met. Marry me!"
The townsfolk all gather at the theatre. Bobby wants to try the show again, but Polly thinks they should give up. The Fodors encourage everyone ("Stiff Upper Lip") but in the end only Polly, Bobby, and Tess vote to continue the show. Everyone exits, leaving Bobby and Polly alone. Bobby tells Polly he's returning to New York ("They Can't Take That Away from Me").
Six weeks later, at his mother's bank in New York, Bobby still dreams of Deadrock and Polly. Mrs. Child gives Bobby the deed to the Zangler Theatre, which she has acquired because Zangler invested all his money in Deadrock. Bobby realizes that Zangler did that for the love of Tess, and love is more valuable than money ("Nice Work If You Can Get It"). Bobby and his mother return to Deadrock to pursue Bobby's great love, Polly.
In Deadrock, which has been transformed into a jewel of a city, Polly walks out of the hugely successful Zangler Follies to go find Bobby. She just misses Bobby and his mother as they enter. As Bobby goes off to find Polly, Irene tells Bobby's mother that she and Lank are now married. Polly returns (her ride ran out of gas) and Tess has an idea: Tess and the gang sing a huge number, bringing Polly and Bobby together at last, and the entire company celebrates (“Finale: I Got Rhythm”).