Simulacron 1 is a highly advanced project, designed to elevate conventional computer technology to a new level by creating a virtual reality inhabited by computer-generated people or 'identity units'. When the head of the project dies mysteriously after showing signs of mental disturbance, Dr Stiller becomes his successor. As he begins to probe deeper into Simulacron, the line between the real and virtual world becomes increasingly blurred and his own existence is questioned.

Rainer Werner Fassbinder's acclaimed science fiction classic has been hugely influential, with themes that would later be explored in films such as The Matrix.