Hollywoodland

In June 1959, Louis Simo, a sleazy Los Angeles private investigator, is spying on the wife of a man named Chester Sinclair to learn if she is having an affair. On a visit to his own ex-wife Laurie, Simo learns that his son is upset over the recent death of actor George Reeves; having been found dead inside his Beverly Hills home with a gunshot wound to the head, which the police ruled as a suicide.
Simo learns from a former police colleague that the Reeves suicide has aspects that the police do not want to touch. Sensing the potential for making a name for himself, Simo begins investigating and notes several apparent conflicts with the official version of Reeves's death. He also bickers with Laurie over his failures as a father, particularly now when his son seems so troubled.
Eight years earlier, Reeves, whose acting career has stalled since appearing in Gone with the Wind, catches the eye of a beautiful woman and they end the night in each other's arms. In the morning, a newspaper photo reveals to Reeves that the woman is Toni Mannix, the wife of Eddie Mannix, the general manager of Metro-Goldwyn-Mayer. Frightened that an affair with a studio boss's wife will destroy what is left of his career, Reeves is angry that Toni did not tell him. She claims to have an open relationship with Mannix and tells Reeves not to worry about it. She also buys the impoverished Reeves a new house and a new car, and lavishes him with jewelry and other luxuries.
Reeves lands the starring role in the television series Adventures of Superman, based on the comic book superhero. The role makes Reeves famous and gives him a steady income, but he longs for more "serious" work and is uncomfortable with the public's stereotype of him as Superman. When a sneak preview of the war film From Here to Eternity results in snickers from the audience when Reeves is seen onscreen, film executives attending the preview decide to drastically reduce his formerly prominent role.
As the years pass, Reeves also becomes embittered at being Toni's kept man and blames her for not using Mannix's influence to get him better roles. He barbecues his Superman costume to "celebrate" the program's cancellation in 1958. He also meets a young woman in New York City, actress Leonore Lemmon, and leaves Toni for her. Toni, brokenhearted and furious, seethes at her "mistreatment" by Reeves.
Simo initially suspects that Leonore might have accidentally shot Reeves during an argument and imagines how the scenario might have played out. Simo is beaten in his home by thugs, apparently working for Mannix, who are trying to scare him off the case. This, and other evidence, leads Simo to suspect that Mannix was the one who had Reeves murdered. Simo also has a vision of how that killing would have occurred.
Simo's original client – Sinclair – murders his wife, having grown impatient waiting for Simo's report. A guilt-plagued Simo gets drunk, then visits his son's school, where his inebriation scares the boy. Simo visits Reeves's manager, Arthur Weissman, who has a home movie that Reeves shot in order to promote some wrestling work. Reeves's sadness and disappointment with his life are evident in the footage. Simo's final imagined variation on Reeves's death concludes with the actor committing suicide. This is the most vivid of the three scenarios, and Simo imagines himself in the upstairs bedroom, watching it unfold.
Each of the scenes imagined by Simo begins with Reeves playing a guitar and singing "Green Eyes (Aquellos Ojos Verdes)" in Spanish for his house guests. After each of the three imagined renditions, Reeves says good night to his guests, then retires to his bedroom upstairs, just before the gunshot.
Reeves's quest for success and Simo's realization of parallels to his own existence cause the detective to re-evaluate his life. Simo watches another home movie, this one of himself, Laurie, and their son in happier days. He goes to Laurie's house wearing a suit and tie, greeting his son hopefully.