As the play begins, Charity Hope Valentine has come to the park to meet her fiancÚ ... or at least the man who will be her fiancÚ as soon as he gets his divorce. She has gone over and over in her head all of the wonderful things he will say to her. When he finally arrives, however, he doesn't say any of these wonderful things, so Charity simply says them for him herself. She then informs him that she has spent the day looking at furniture and has brought her life's savings to put a down payment on their new home. Full of hopes and dreams, she looks down at the lake and suggests that they should throw something in for good luck. The young man complies, throwing Charity in and running off with her purse! A crowd gathers, and soon Charity is obliged to tell her story to the police.
We next find Charity at her place of employment, the Fan-Dango ballroom where she works as a dance hostess. The other girls are not surprised by the previous night's adventure; they've heard it all before. And in spite of poetic freedoms she allows herself when telling the story, Charity finally has to admit that she's been taken for a sucker once more, and vows that this will be the last time. No man will ever again make a fool out of her!
On her way home, just as Charity passes the swank Pompeii Club, a man rushes out of the club and knocks her over. She is amazed to discover that it is the famous movie star Vittorio Vidal, and even more amazed to find that he is quarrelling with a woman, his mistress, to be more precise. Charity watches in fascination as the argument escalates. Finally, as a gesture of contempt for his mistress, Vittorio grabs the first woman he sees and sweeps her into the Pompeii Club as his new partner. This woman, of course, is Charity. Once inside, Vittorio talks mostly about his mistress, Ursala, but Charity doesn't care - she is enjoying the glitz and glamour of the fancy club. It is all a little much for her, however, and Charity faints. When she comes to in Vittorio's apartment, she asks him for an autographed picture to prove to her friends that she was really here. He is about to give her much more than that when Ursala begins banging on the apartment door. Charity hides in a cupboard while Vittorio and Ursala make up. Ursala is still lounging in bed the next morning when Vittorio sneaks Charity out of the house.
The next day, Charity's friends reprimand her for letting a man of such wealth slip through her fingers. After all, he could have been her ticket out of the Fan-Dango. But Charity doesn't care. The adventure has, however, inspired her to get out and meet new people in new places, so that night she goes to the local YMCA. The evening doesn't go quite as planned, and she finds herself trapped in an elevator with a claustrophobic tax accountant named Oscar. After they are rescued, Oscar invites Charity to go to church with him. She accepts and soon learns that Oscar's church is a little unusual, apparently having sprung from a jazz group. Their leader seems to be a cat named Daddy Johann Sebastian Brubeck who preaches mostly of welfare and drug resolutions. It is not that surprising when the police arrive and throw the whole congregation out on the street. In spite of all this, Charity finds that she has a growing fondness for Oscar. He is different than the other men she has dated. He doesn't try to get her into bed, and he calls her "Sweet Charity." He seems to be under the impression that Charity is a bank clerk, and although Charity chooses for the moment not to correct him, she promises to tell him the truth about her job soon.
Charity and Oscar go to Coney Island on a date and once again find themselves stuck, this time at the top of the parachute jump. Charity is really scared this time, but Oscar calms her. She tries to tell him about her job, but he kisses her, and she decides to wait a little longer. Inspired by her budding love, Charity decides to quit the Fan-Dango. She then sends Oscar a telegram telling him to meet her at a certain restaurant and state his intentions. She tells him about the Fan-Dango, and he doesn't care; he wants to marry her anyway. Charity is overjoyed. Her friends at the Fan-Dango throw her a going-away party. Everything looks like it is going to work out--just like a fairy tale! Then Oscar chickens out. He thought he could forget all of the other men Charity has slept with, but he just can't get them out of his mind. Charity meets him in the park to try to change his mind, but she only winds up falling once more into the lake. As she climbs out, soaked and dripping, she is surprised to find a Good Fairy with real wings and all covered in tinsel-dust. The fairy tells her, "Tonight. It will all happen tonight." This seems to make everything okay, and Charity, once more full of hopes and dreams for the future, goes on her merry way. As the Good Fairy turns around, however, we see a sign on her back which reads: "THE GOOD FAIRY--tonight at 8 P.M. on CBS."