The plot of the film is a humorous and satirical autobiography of Hollywood's difficult transitional period from silent film to 'talkies'. The story is set in glamorous 1927 Hollywood. Gene Kelly, as Don Lockwood, plays a dashing, and somewhat smug romantic film star. His gorgeous, blonde on-screen partner, Lina Lamont, is portrayed by Jean Hagen. She delivers a smashing performance as the ditzy, love struck diva with a very bad voice. The two stars are expected to pretend to be involved romantically by studio heads for publicity purposes. Don has no interest in Lina that way; but she refuses to believe him, deciding he is playing hard-to-get, making a very amusing complication in the narrative. The real trouble comes when they are instructed to move from silent film to the new domain of talking film, making their debut in The Dancing Cavalier. Lina's screechy and shrill voice has a thick New Yorker accent. Even with speech specialists and tutoring, her voice cannot be conquered.
While the cast and crew are trying to figure out what to do about the problem, Don runs into Kathy, played by the charming Debbie Reynolds, an aspiring actress/dancer. Don is escaping from a mob of fans and jumps into her moving convertible. After a tussled beginning the two start dating. Cosmo, Don's ex song-and-dance partner, depicted by Donald O'Conner, suggests that Kathy's phenomenal voice be dubbed in for Lina, but kept secret from her. The plot thickens as Lina becomes more jealous of Kathy and Don and eventually finds out about the behind the scenes work to disguise her voice. But Don and Cosmo's scheming to expose the jealous Lina and give Kathy the limelight as the real voice for the movie Lina provides a happy resolution and smooth transition into sound pictures.