Charity Valentine is the eternal optimist. While working at the seedy Fan-Dango Ballroom, she is often exploited by men, and has been strung along in a series of bad relationships. Nonetheless, she always holds out hope -- and she seems to have finally met a decent fellow in Oscar. Concerned that he will reject her if he discovers her true profession, Charity lies to Oscar tells him that she works in a bank. Soon, Oscar asks Charity to marry him. Unfortunately, when Oscar discovers Charity's real profession, he backs out of the marriage. Based on Federico Fellini's screenplay for Nights of Cabiria, Sweet Charity follows Charity's romantic ups and downs as she remains ever-hopeful that, despite her work as a prostitute and dancer-for-hire, she will ultimately find love!