In the present day, the Institute for Cybernetics and Futurology's (Institut für Kybernetik und Zukunftsforschung) new supercomputer hosts a simulation program that includes an artificial world with more than 9,000 "identity units" who live as human beings, unaware that their world is just a simulation. Professor Vollmer (Adrian Hoven), who is the technical director of the program, is apparently on the verge of an incredible secret discovery. He becomes increasingly agitated and anti-social before dying in a mysterious accident. His successor, Dr. Fred Stiller, has a discussion with Günther Lause, the security adviser of the institute when the latter suddenly disappears without a trace before he is able to pass on Vollmer's secret to Stiller. More mysterious still is the fact that none of the other IKZ employees seem to have any memory of Lause.
Meanwhile, one of the identity units in the simulation attempts suicide. This unit is deleted by Stiller's colleague Walfang to keep the simulation stable. To investigate the reasons for the suicide, Stiller enters into the simulated world to interview the contact unit. The unit, called Einstein, is the only identity unit that knows the "world" is a simulation, and this is necessary to run the program. In an attempt to become a real person, Einstein switches his mind into Walfang's body while Stiller is in contact with the simulated world. Einstein gives Stiller an explanation for the mysteries, vanishing memories, and vanishing persons, telling him that Stiller's "real world" is nothing but a simulation of the real world, which is one level above.
This knowledge causes Stiller to slip into insanity. The other "real" people interrogate Stiller and he is threatened with death, incarceration, and involuntary commitment. Stiller is finally able to convince Hahn, the IKZ psychologist, of his theory. The latter soon dies in an accident that is pinned on Stiller, marking him as the suspected murderer of both Hahn and Vollmer.
Stiller flees and searches for the necessary contact unit who can connect his "real" world with the real world, a level above. He survives several assassination attempts and discovers the contact is Eva, who was projected into the simulation after Vollmer's death (as his non-existent daughter). Stiller accepts her presence, believing they once had a romance. Eva tells him he was modeled on the real Fred Stiller, a person whom Eva loved, but who went mad with power from directing the simulation in the world above. While Stiller is programmed to die in an ambush, Eva switches the minds of the two Stillers and brings the simulated Stiller into the real world.
Music
The martial folk song "Westerwaldlied" and standard German love song "Lili Marleen" are both featured in an extended scene in which Stiller seeks temporary respite in a cabaret. During the Siskins house party scene early in the movie, Ingrid Caven sings the song "The Boys in the Back Room". "The instrumental "Albatross" by Fleetwood Mac plays during the credits of both parts, as well as a scene in Part 2.
The series was released on Blu-ray and two-disc DVD by The Criterion Collection in February 2012.[5] The Criterion release is using the 24 frames per second native blu-ray HD encoding system.[6] It was also released on limited edition Blu-ray by Second Sight in February 2019, simulating 25 frames per second of the PAL system.[7][6]
