It's the proverbial end of the summer 1962 in a small southern California town. It's the evening before best friends and recent high school graduates, Curt Henderson and Steve Bolander, are scheduled to leave town to head to college back east. Curt, who received a lucrative local scholarship, is seen as the promise that their class holds. But Curt is having second thoughts about leaving what Steve basically sees as their dead end town. Curt's beliefs are strengthened when he spots an unknown beautiful blonde in a T-bird who mouths the words "I love you" to him. As Curt tries to find that blonde while trying to get away from a local gang who have him somewhat hostage, Curt may come to a decision about his immediate future. Outgoing class president Steve, on the other hand, wants to leave, despite meaning that he will leave girlfriend, head cheerleader and Curt's sister, Laurie Henderson, behind. Steve and Laurie spend the evening "negotiating" the state of their relationship. Meanwhile, two of their friends cruise around town for the evening. Steve has left his car to meek and mild-mannered Terry "Toad" Fields to look after during his absence. The wheels give Toad a new sense of confidence, which he uses to try and impress Debbie Dunham, a more experienced girl generally out of his league. And John Milner, who is seen as the king of the street race in his souped-up yellow deuce coupe, tries to get rid of precocious pre-teen, Carol Morrison, who has somehow become his passenger for the evening, while dealing with the challenge of bold out-of-towner, Bob Falfa.

The Imperial Forces, under orders from cruel Darth Vader, hold Princess Leia hostage in their efforts to quell the rebellion against the Galactic Empire. Luke Skywalker and Han Solo, captain of the Millennium Falcon, work together with the companionable droid duo R2-D2 and C-3PO to rescue the beautiful princess, help the Rebel Alliance and restore freedom and justice to the Galaxy.

It's sometime in the future in a state controlled society, where conformity and homogeneity are the rule. What is also the rule is that the populace follows the wants of the faceless state without question. How this is achieved is through a mandatory drug regimen, which also suppresses human desire, with sexual intercourse and human relationships banned. The law of the state is policed by a force of robocops. The physical environment is totally within a manufactured enclosure, what being outside of this unknown. THX 1138 is a loyal subject, he who goes about his business as a skilled factory working building robocops. And even when he begins to have strange feelings, he does what is obliged by going to the state run confessional, which further brainwashes through its reinforced mantra of happiness, loyalty and understanding. THX 1138 is given a glimpse into the other side through his computer matched and thus appointed female roommate, LUH 3417, and her surveillance colleague SEN 5241, LUH 3417's vision which may be something that THX 1138 may want to continue despite its illegality. If THX 1138 is able to keep his activities from the authorities and the robocops, he will have to figure out what options are available to him.