This beloved classic opens with silent picture star Don Lockwood (played by Gene Kelly) telling the audience of how he and his friend Cosmo Brown (played by Donald O'Connor) worked their way up on various films until they got their respective big breaks. Don initially started out as an accompanist to Cosmo's piano but managed through hard work to end up in front of the camera. He ends up starring alongside the beautiful and admired Lina Lamont (played by Jean Hagen) and the two become Hollywood darlings with an enthusiastic audience that loves everything that they do.
After Don reminisces Don, Lina, and Cosmo go into a theatre to introduce the latest Don and Lina silent romance movie. The audience loves it and Don and Lina come onto the stage to thank the audience. It is at this time that the viewing audience is made aware that there are problems between Don and Lina as well as with Lina in general. It seems that she has a bit of a screechy, nasally voice that is anything but pleasant to the ears. Also Lina is so full of herself that she assumes that she and Don are a real-life item when Don is beyond uninterested. After Don, Lina, and Cosmo have a brief conversation, Don leaves the theatre to rejoin the group at a house party in celebration of their latest success.
Along the way to the party, Don gets mobbed by enthusiastic fans and in his effort to flee, ends up in the car of a lovely young woman named Kathy Selden (played by Debbie Reynolds). At first Kathy is naturally upset but after realizing that Don Lockwood is in her car, she calms down. Before Don can completely relax Kathy starts to criticize Don by saying that he isn't really acting since he is in silent pictures. Don is affronted. Kathy drops Don off at his location then disappears.
While Don is still trying to get over his bruised ego at the party, a new technology involving talking that the audience can hear while the speaker on screen is talking is revealed. Everyone brushes it off as something ridiculous. Some even laugh. No one is taking it seriously in the slightest.
At this time a group of dancing girls from a nearby club come out to entertain the audience and who should be a member but the critical Kathy. Don is amused and delighted to see her if only for the chance to give her a hard time after she was so full of criticism for him. Kathy is embarrassed and put off and leaves after finishing the number.
Shortly after the party, Don, Lina, and Cosmo are told by the studio head that the studio will be making "talkies" from now on after the enormous success of The Jazz Singer. Everyone is appalled because this is a huge change. Some were worried about what would happen to people who couldn't speak well or didn't have nice voices. Lina isn't worried because she doesn't think that there is anything wrong with her voice.
Since the party, Don and Cosmo have been looking for Kathy partly to help her get her big break and partly because Don is smitten with Kathy. After Cosmo spies Kathy performing in a musical number in a "talkie" picture he finds Don and brings him over. Fortunately for Kathy the studio head also observes Kathy during the musical number and decides to cast her in a minor role in the latest Don and Lina picture. Don heartily agrees with the casting choice. Everyone agrees to keep Lina out of the loop due to Lina's jealousy and meanness.
