This movie is very stylized. To the point where it’s hard to figure out what is going on. To the point where it’s really impossible to describe anything that goes on on anything other than a metaphorical level. It shows 2 people that live in a futuristic society where individualism is discouraged. People are given designators like “THX 138” (the main character). Empty consumerism is taken to the furthest extremes—the citizens are encouraged to buy strange geometric objects that they immediately take home and dispose of. They talk about their problems to large automated video screens that at first seem to be listening but on closer inspection look like they’re just running some sort of looped video of a man’s face repeating soothing phrases. They are compulsorily heavily medicated. They are encouraged to not have emotional attachments.
So what happens when one of them rebels? Well most of the movie is about THX 1138’s journey out of the society. Sadly, the last huge chunk of the movie is basically a giant chase scene which derails the sort of introspective pace the beginning of the movie had. It ends kind of abruptly and doesn’t really answer any questions about itself satisfactorily. I think it’s worth watching, but don’t expect either an action packed sci-fi adventure (see “Star Wars” for that) or any answers to your questions.