[3][4] In an underground city in a dystopian future, the protagonist, whose name is "THX 1138 4EB", is shown running through passageways and enclosed spaces.

[1] Lucas had an idea for a long time "based on the concept that we live in the future and that you could make a futuristic film using existing stuff".

[5] Years later, in "The Making of THX 1138" DVD featurette, Robbins recalls that the "EB" in the title (and the character's serial number name) stands for "Earth born".

[5][7] However, the Navy paid for unlimited color film and lab processing costs for their students.

In the final scene, people are warned not to exit the underground city through the door, which allegedly leads to death.

Cosmetically, there are similarities in coloring and appearance, although one noticeable difference is the actors did not have to shave their heads for the short film, unlike the later feature version.