Laurie Robinson is a young woman who earns a living by performing in commercials and hosting a children's show on public television, but she would rather concentrate on songwriting and singing than doing comedy with her small-time comedian father Si. One night, Laurie goes to a restaurant where she meets a young film director, Chris Nolan; she drives him back to his apartment and they spend the night together. The next morning, Laurie confesses to Chris that she is engaged and has to be at her wedding rehearsal. He asks if the previous night was just a final fling before marriage, and she says she cannot see him anymore.
Laurie later meets with her fiancé, Ken Rothenberg, and attends a recording session where she records her song, then sings background vocals and directs the musicians during overdubs. From there, she goes to the wedding rehearsal where Si has arranged an elaborate setup with an old friend who owns the Wedding Palace. The next day, Laurie auditions for a film that needs a singing voice for the leading lady. The director, she discovers, is Chris, who is as surprised as she is. Chris asks to see the songs in her portfolio. Laurie's voice and the orchestra's performance of her song You Light Up My Life impresses everyone, and Chris asks her if she would be interested in auditioning for the lead in his movie.
Later, Chris sings You Light Up My Life for Laurie at his piano, giving it a more subdued treatment, then takes her for a walk along the beach. Laurie visits her best friend Annie to confess that she loves Chris, and adds that she may have the lead in his film. Meanwhile, when Laurie meets with Ken to call off the wedding, Chris auditions another girl for his movie and tells her she has the part, then gives his assistant the job of calling Laurie with the bad news. When Laurie asks why Chris did not call himself, the assistant explains that Chris has been in meetings all afternoon, and when she calls Chris's office, the receptionist tells her he is probably at home because he does not have any meetings. Laurie arrives at Chris's apartment as he and his new leading lady are leaving for dinner with friends. He apologizes and tells her she is special enough to get other roles.
Later that night, when Laurie and Si perform at the Family Komedy Hour, her routine falls flat, tears flood her eyes and she walks off. In the dressing room, Laurie tells Si she hates the act because she is not funny, all she wants to do is sing and that Columbia Records is interested in her. She gives Si a cassette tape of her songs and tells him he has to let go of her, because she needs to depend on herself; she is going to New York City alone. They hug and kiss goodbye, and Laurie drives away. Sometime later, Laurie's You Light Up My Life climbs the music charts and reaches number one.
