Julian Marsh, a successful Broadway director, produces a new show, in spite of his poor health. The money comes from a rich older man, who is in love with the star of the show, Dorothy Brock. But Dorothy doesn't respond to his love, because she's still in love with her old partner. On the night before the premiere, Dorothy breaks her ankle, and Peggy Sawyer, one of the chorus girls, tries to take over Dorothy's part.

42nd Street is a 1933 American Warner Bros. musical film directed by Lloyd Bacon with choreography by Busby Berkeley. The songs were written by Harry Warren (music) and Al Dubin (lyrics), and the script was written by Rian James and James Seymour, with Whitney Bolton (uncredited), from the novel of the same name by Bradford Ropes.

The film is a backstage musical, and was very successful at the box office. 42nd Street was nominated for the Academy Award for Best Picture in 1934, and in 1998 it was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant". In 2006 this film ranked 13th on the American Film Institute's list of best musicals.