In New York City in 1933, dance director Andie Lee is auditioning kids for the chorus of a new show called Pretty Lady (“Audition”). The show’s writers, Bert and Maggie, are pleased with what they see on stage, but they warn the dancers that at $4.40 per seat, the audience will demand some spectacular dancing. Young hopeful Peggy Sawyer just misses the audition, but Billy – the show’s romantic lead – helps her see the Director (“Young and Healthy”).
The Director, Julian Marsh, has no patience for latecomers, and Peggy rushes off the stage. Julian tells Bert and Maggie he’s worried about some of the cast, especially Dorothy Brock, the leading lady. Her last hit was ten years earlier, but her "Sugar Daddy", Abner Dillon, is backing the show. Just then Dorothy and Abner arrive, and Julian suggests that Dorothy audition. Abner defends Dorothy and reminds Julian that Dorothy does not have to try out for anyone (“Shadow Waltz”).
Realizing she has forgotten her purse, Peggy returns to the stage. Maggie invites her to lunch with three of the girls, and the five women dance off stage. As they settle in at the Gypsy Tea Kettle, the girls are astonished by Peggy’s naïveté. They amusingly explain the Broadway facts of life, and dance back to the theater (“Go into Your Dance”). The number evolves into an audition for Peggy, who impresses Julian and lands a job in the chorus.
Dorothy and Billy begin rehearsing their big love scene. Abner objects to their kissing...leading to a rather awkward exchange. (“You’re Getting to be a Habit With Me”). Peggy, weak and overcome by an overwhelming day, faints on stage. She is carried to Dorothy’s dressing room, where Pat Denning, Dorothy’s boyfriend, is waiting. Dorothy walks in, misreads what she sees, leading to plenty more drama.
The company packs up for previews in Philadelphia (“Getting Out of Town”), and dress rehearsals begin (“Dames”). After rehearsal, Peggy invites Julian to join her at an impromptu cast party. Captivated by her charm, Julian decides to go. Dorothy, who misses Pat, drinks a bit too much, and tells Abner to take his money and leave. Abner is ready to close the show, but the kids talk him out of it. After kicking him out of her room, Dorothy sings of her love for Pat ("I Only Have Eyes For You").
Pretty Lady opens spectacularly with “We’re In the Money.” But when Dorothy rushes onstage for the Act I finale, she is accidentally knocked down by Peggy and can’t get up. Julian, furious, fires Peggy and cancels the rest of the performance.
Act II opens with a doctor telling Julian that Dorothy’s ankle is broken. Julian says he will close Pretty Lady for good, but the cast won’t give up (“Sunny Side to Every Situation”). The cast thinks that Peggy can save the day, and Julian finally agrees. Peggy has already left for the train station, so Julian rushes after her. Julian, helped by the rest of the Company, convinces Peggy to return (“Lullabye of Broadway”).
Peggy has exactly 36 hours to learn 25 pages, 6 songs, and 10 dance numbers. At long last, the Broadway curtain opens on Pretty Lady (“Shuffle Off to Buffalo”). The show is a spectacular hit, and Peggy Sawyer is a sudden sensation. Julian leads the entire company in celebrating the glory of “42ND STREET.”
