Truman Burbank is the cheerful and unsuspecting star of The Truman Show, a reality television program that is filmed through thousands of hidden cameras 24 hours a day and broadcast to a worldwide audience. Christof, the show’s creator and executive producer, seeks to capture Truman’s authentic emotions and give audiences a relatable everyman. As Truman was selected from a number of unwanted pregnancies, Christof claims that Truman came to be adopted not just by the show, but by the “world”. Truman’s hometown of Seahaven Island is a complete set built within an enormous dome and populated by actors and crew members, allowing Christof to control almost every aspect of Truman’s life, including the weather. To prevent Truman from discovering his false reality, Christof manufactures scenarios that dissuade Truman’s desire for exploration such as killing off his father in a sea storm to instill aquaphobia, and by constantly broadcasting and printing messages of the dangers of traveling and the virtues of staying home. However, Christof cannot predict all of Truman’s actions. During his college years, Truman was intended to fall in love with and marry co-student Meryl, but fell for Sylvia, an extra. Although Sylvia was quickly removed from the show before she could disclose its nature to Truman, her memory has remained with Truman, who secretly dreams of a life with Sylvia outside of his marriage to Meryl. To this end, he seeks travel to Fiji, where he was told Sylvia’s family moved to. In the real world, Sylvia is a part of the “Free Truman” campaign, which fights to have Truman released from the program.
During the show’s 30th anniversary, Truman begins discovering unusual elements such as a spotlight falling out of the sky in front of his house and a radio channel that precisely describes his movements. These events are punctuated by the reappearance of his father, who had infiltrated the set as a beggar. Truman begins questioning his life and realizes that the city somehow revolves around him. Meryl’s stress from attempting to uphold the charade in the face of Truman’s growing skepticism and hostility causes their marriage to deteriorate. One day, Truman takes Meryl by surprise by going on an impromptu road trip, but their way is blocked by increasingly implausible emergencies. During an argument in which Truman determines that Meryl is a part of the conspiracy and holds her at knife-point, she breaks character and is taken off the show. Hoping to bring Truman back to a controllable state, Christof re-introduces Truman’s father to the show properly, under the guise of having lost his memory after the boating accident. This helps the show regain the ratings lead with audiences, and Truman seems to return to his routines, except he begins sleeping in his basement. One night, Truman secretly disappears through a makeshift tunnel in his basement, forcing Christof to temporarily suspend the broadcast for the first time in its history. Audiences and the media, as well as Sylvia, are captivated by this sudden change.
Christof orders a citywide search for Truman, and is soon forced to “cue the sun” and break the production’s day–night cycle to optimize the search. Christof discovers Truman sailing away from Seahaven on a small boat, having conquered his fear of water. After resuming the transmission, Christof creates a violent storm in an attempt to capsize the boat. However, Truman’s determination convinces Christof to end the storm. Truman continues to sail until his boat pierces the wall of the dome. Initially horrified, Truman discovers a nearby staircase leading to an exit door. As Truman contemplates leaving his world, Christof speaks directly to Truman through a speaker system and tries to persuade him to stay, claiming there is no more truth in the real world than in his artificial one, where he would have nothing to fear. After a moment of reflection, Truman says his catchphrase: “In case I don’t see you… good afternoon, good evening, and good night”, bows to his audience and exits. The viewers celebrate his escape and Sylvia races to greet him. Defeated, Christof’s supervisors finally end the program on a shot of the open exit door, and Truman’s former viewers begin looking for something else to watch.