Directed by Billy Wilder, an aging movie star and her admiring butler take in a struggling screenwriter who becomes her lover.
Police find a murdered screenwriter floating in a pool. Joe Gillis (William Holden) tells his story. He is broke and may lose his car. Sheldrake (Fred Clark) rejects his baseball script because reader Betty Schaefer (Nancy Olson) didn’t like it. Joe loses his agent.
While fleeing repossessors, Joe gets a flat and puts his car in a large garage. Max von Mayerling (Erich von Stroheim) sends him upstairs to expectant Norma Desmond (Gloria Swanson), who wants her dead monkey buried. Norma was a movie star and learns he is a writer. She has a script about Salomé and asks him to read a scene. Joe says it is good, but it needs editing. Joe says he gets $500 a week, and she says he must stay there to work.
Joe wakes and finds his belongings there. Max says he brought them. Joe accepts the job. He works, and at night they watch her silent movies. Norma plays bridge with actors. Max tells Joe they are towing away his car. Norma says she has a car. They go for a ride, and Norma buys Joe clothes.
Rain and a leaky roof causes Joe to move into the main house. Max tells Joe that Norma is suicidal. At her New Year’s party Norma dances with Joe, the only guest. He tells her to stop buying him things and that he is wrong for her. She slaps him. Joe goes out and hitches a ride to a party. Artie Green (Jack Webb) says he can stay there. Betty tells Joe that she likes one of his stories. Joe calls Max and asks him to pack his old clothes. Max says that Norma cut her wrists. Joe rushes back, and Norma says she fell in love with him. Joe thanks her for helping him. Norma cries, and Joe wishes her a happy new year.
Betty calls for Joe, but Max says he is not there. Norma tells Max to take her script to Cecil B. DeMille. In a drugstore Joe sees Artie and Betty, who wants him to work on a script.
Norma entertains bored Joe. She declines calls from Paramount and goes to see DeMille (himself) on the lot. He welcomes her and learns they have been calling her to rent her antique car. DeMille tells Norma that the picture would be expensive. Joe sees Betty and says she can have the script, but she wants to work with him. Max tells Joe that they want Norma’s car.
Norma gets beauty treatments to prepare for her role. Joe sneaks out at night to work on the script with Betty. Max cautions Joe and says he protects Norma and was her first husband and director.
Norma is jealous and finds Joe’s love story co-authored by Betty. Joe learns that Betty can’t marry Artie because she is in love with him.
Joe hears Norma call Betty and grabs the phone, suggesting she come there. Norma cries. Betty arrives, and Joe tells her he is living with Norma. He sends Betty back to Artie. Norma thanks Joe, who packs. Norma gets her gun. Joe tells her that DeMille does not want her, but Max says she is the greatest star. Joe walks out, and she shoots him; he falls into the pool. Joe narrates the removal of the body. Hedda Hopper (herself) calls in the story. Police question Norma. She comes down for the cameras, and DeMille directs her. Norma says she is happy to be acting again.
This pathetic drama exposes how a fabulously successful movie star may become miserable and self-deceiving after she is no longer wanted. Her riches are contrasted to the poverty of a writer who compromises himself to survive.