High tech drama

In the present day, a supercomputer has been developed at the Institute for Cybernetics and Future Science, running software called Simulacron, which includes an artificial world with over 9,000 "identity units" living as human beings, though unaware that their world is a simulation.  The program's technical director Professor Vollmer is on the verge of making an incredible discovery, when he dies mysteriously.

His successor, Dr. Fred Stiller, has a discussion with the institute's security adviser Günther Lause, but then the latter suddenly disappears without a trace. More mysterious still is the fact that no one else seems to have any memory of Lause. Stiller investigates the strange case — what he finds is even stranger.