It’s 1922, and Millie Dillmount has just escaped to New York City from Salina, Kansas, and, determined to become a success, tears up her return ticket. Bobbing her hair, she assumes the modern look of a “flapper”. But she is quickly mugged on the streets of New York, losing her hat, scarf, purse and shoe. In a panic for someone to help her, she trips by-passer Jimmy Smith, a handsome, carefree young man who makes his way through life on whim and wits, who promptly lectures her on why she needs to head back home: she is just another girl full of false hopes who doesn’t belong in the big city. Almost taking his advice, she changes her mind and yells after him, “Who needs a hat? Who needs a purse? And who needs YOU, mister whoever-you-are?!” and soon takes a room at the Hotel Priscilla for Single Women.
A week later, Millie is confronted by the hotel proprietress, the mysterious and sinister Mrs. Meers, an actress turned evil who now works for a white slavery ring in Hong Kong, kidnapping pretty unsuspecting orphan girls and shipping them to the Orient, which she has just done to Millie’s hall mate, Ethel Peas. Mrs. Meers declares that Millie “has two minutes to pack, or find her things on the street!” But then Millie meets the wealthy Miss Dorothy, who wants to learn how the poorer half-lives, and wants a room in the Hotel Priscilla. Millie, seeing this as a way to get her rent paid, suggests that Miss Dorothy can room with her until she can find her own, but only if Miss Dorothy pays the rent. Mrs. Meers, comes out of her office, saying Millie can get a rent extension, and Miss Dorothy can take the “Nice, sunny room that just become available, right next to Millie’s.” When Millie asks what happened to her old neighbor, Ethel, Mrs. Meers says she got an acting job in the Orient. Millie and Miss Dorothy then go up to their rooms, tap dancing to get the elevator to start.
In the Hotel Priscilla laundry room, two Chinese immigrants, Ching Ho and Bun Foo, are working for Mrs. Meers to earn enough money to bring their mother from Hong Kong over to the states.
After researching some of the richest and most eligible bachelors in the world, Millie comes to Sincere Trust not only looking for a job, but also to set her sights on the company’s boss, Trevor Graydon III. Her lightning speed stenography easily lands her the job. Meanwhile, Ching Ho attempts to capture Miss Dorothy for Mrs. Meers with a drugged apple but when he sees her, falls in love with her instantly and then wants to save her from Mrs. Meers. Before Dorothy eats the drugged apple, Millie arrives, (Mrs. Meers has to act like she was getting a stain out of the carpet with “Soy Sauce”) with the good news that she has found a job and a boss to marry. As the girls rush off to their rooms, Mrs. Meers thinks about how stupid the girls are to never realize she’s an evil mastermind trying to ship them to Southeast Asia. To celebrate their success the girls go to a speakeasy, where they meet Jimmy, but the club is raided by the police. While waiting for his release in the jail cell, Jimmy realizes that he loves Millie.
Jimmy asks Millie to a party hosted by famous singer Muzzy van Hossmere, and she accepts. Before the party Muzzy sings of her love for New York. At the party, Millie spills wine on Dorothy Parker’s dress, which Millie tries to get out with soy sauce, following Mrs. Meers’ example. After the party, Millie explains to Jimmy how she is going to marry Trevor. She also tells him off for being a “skirt chaser” and “womanizer”. As they argue, Jimmy suddenly grabs Millie and kisses her, then runs away. Millie realizes that she loves Jimmy. Millie returns to the hotel and overhears a conversation between Miss Dorothy and Jimmy, “I really want to tell her, she’s my best friend” “You know we can’t”. Millie sees Jimmy sneaking out of Miss Dorothy’s room after what appears to be a late-night tryst; confused and horrified, Millie decides she never wants anything to do with Jimmy ever again.