In a drab, futuristic underground world, a cowered and dehumanised populace is governed by a central computer; a robotic police force controls all aspects of daily life in true totalitarian fashion, stamping out any sign of individuality The inhabitants dress in regulation white and their heads are shaved. THX 1138 (Robert Duval!) and LUH 3417 (Maggie McOmie) fail in love but transgress strict laws which forbid sex (regarded as a privilege, not a right), and a drug offense which means not taking your daily dose of state-issued tranquilliser.

The stark, technologically sterile settings are shot in a desaturated colour scheme devoid of human emotion —a sharp contrast to the colour and movement of the higher budget Raiders and Star Wars series. THX 1138 was originally produced as a 20 minule short at UCLA where Lucas was a film student, with the sponsorship of his mentor Francis Coppola (he would later executive produce American Graffiti in 1973).

Coppola chose this project as the first release for his American Zoetrope company, based in San Francisco, and permission was obtained to film in the Alphaville-style environment of the Bay Area Rapid Transit (BART) tunnels which were then under construction beneath San Francisco Bay. The troubled film, although shot in 1969, was kept on the shelf by Warner Brothers until 1971.