In Hollywood, director Fred Amiel (Sullivan), movie star Georgia Lorrison (Turner), and screenwriter James Lee Bartlow (Powell) each refuse to speak by phone to Jonathan Shields (Douglas) in Paris. Movie producer Harry Pebbel (Pidgeon) gathers them in his office and explains that Shields has a new film idea and he wants the three of them for the project. Shields cannot get financing on his own, but with their names attached, there would be no problem. Pebbel asks the three to allow him to get Shields on the phone before they give their final answer.
As they await Shields' call, Pebbel assures the three that he understands why they refused to speak to Shields. Their involvement with Shields then unfolds in a series of flashbacks. Shields is the son of a notorious former studio head who had been dumped by the industry. The elder Shields was so unpopular that his son had to hire extras to attend his funeral. Despite the ill feelings toward him because of his father, the younger Shields is determined to make it in Hollywood.

Shields partners with aspiring director Amiel, whom he meets at the funeral. Shields intentionally loses money he does not have in a poker game to film executive Pebbel so he can talk Pebbel into letting him work off the debt as a line producer. Shields and Amiel learn their respective trades making B movies for Pebbel. When one of their films becomes a hit, Amiel decides they are ready to take on a more significant project he has been nursing along, and Shields pitches it to the studio. Shields gets a $1 million budget to produce the film, but betrays Amiel by allowing someone with an established reputation to direct. The film's success allows Shields to start his own studio, and Pebbel goes to work for him. Amiel becomes an Oscar-winning director.

Shields next encounters alcoholic small-time actress Lorrison, the daughter of a famous actor Shields admired. He builds up her confidence and gives her the leading role in one of his movies over everyone else's objections. When she falls in love with him, he lets her think that he feels the same way so that she does not self-destruct and he gets the performance he needs. After the premiere makes her a star overnight, she finds him with a bit player named Lila. He tells her that he will never allow anyone to have that much control over him. Crushed, Lorrison walks out on her contract. Rather than suing her, Shields lets her go to another studio. She becomes a top Hollywood star.

Finally, Bartlow is a contented professor at a small college who has written a bestselling book for which Shields has purchased the film rights. Shields wants Bartlow himself to write the script. Bartlow is not interested, but his shallow Southern belle wife Rosemary is, so he gives in. They go to Hollywood, where her constant distractions keep him from his work. Shields gets his suave actor friend Victor "Gaucho" Ribera to keep her occupied. Freed from interruption, Bartlow makes excellent progress on the script. Rosemary, however, runs away with Gaucho; they are killed in a plane crash. When the script is completed, Shields has the distraught Bartlow remain in Hollywood to help with the production, while Shields takes over directing duties. A first-time director, Shields botches the job, which leads to his bankruptcy. Then Shields lets slip his part in Rosemary's involvement with Gaucho, so Bartlow walks out on him. Bartlow goes on to write a novel based upon his wife (something Shields had encouraged him to do) and wins a Pulitzer Prize.

After each flashback, Pebbel sarcastically agrees that Shields "ruined" their lives; each of the three is now at the top of their respective professions, thanks largely to Shields. At last, Shields's call comes through and Pebbel asks the three if they will work with Shields just one more time; all three say no. As they leave, Pebbel is still talking to Shields. The three eavesdrop on an extension phone as Shields describes his new idea; they become more and more interested.