Preface: Watch the Thirteenth Floor to experience the sound, the look, and the feel of the film. Along the way, viewers can make their own mental journey. A list of events from the movie does not describe what is important or admirable about this work.
In a letter to Douglas Hall from his boss and friend, Hannon Fuller:
"They say ignorance is bliss. For the first time in my life, I agree. I wish I had never uncovered the awful truth. I know now. Once they find out, they will try to silence me. That is why I have written this all down for you in this letter. You are the only one I can tell this to, the only one who could possibly understand. Good luck, my friend."
Hannon Fuller is the head of a computer software company in present day Los Angeles. Mr. Fuller is murdered shortly after the completion of a virtual world which is capable of being accessed by the users. LAPD detective, Larry McBain, suspects that Douglas Hall, Fuller's partner and recently named heir, is the killer. Even Mr. Hall suspects himself as Hannon Fuller's murderer. Although he has no memory of that night, he did find a bloodstained shirt in his bathroom the following morning.
In the course of an investigation, a tearful young woman appears in Hannon Fuller's apartment. She introduces herself to Mr. Hall and the detective as Jane Fuller, Hannon's daughter. Douglas Hall is astounded since his partner never mentioned a daughter in all the years they had worked together.
Douglas returns to work and consults with his equally grief-stricken partner, Whitney. They search the system and discover that Fuller had been downloading himself, accessing the virtual world of Los Angeles in the 1930s. The simulation is populated by fully formed self-learning cyber beings who think, work and eat like ordinary people. A message suggests that Fuller left important information about his killer somewhere in that world.
In spite of Whitney's warnings, Mr. Hall feels compelled to follow Hannon Fuller's trail through the system to discover the truth about the murder. With Whitney monitoring the equipment, Doug Hall downloads into the body of his virtual double, John Ferguson, who is currently working as a bank teller. Amazed by the intricacy and beauty of the virtual world they have created, Hall wanders through the streets of 1937 Los Angeles. He encounters Whitney's double, a bar tender named Ashton. He also speaks with Hannon Fuller's double, Mr. Grierson, at his shop. Unfortunately, neither of these characters supply the needed information about the murder. Douglas Hall's time in the simulation expires, and he exits the body of John Ferguson, leaving a very curious bar tender as witness to this event.
Meanwhile, the continuing investigation by Detective McBain is gathering evidence that points to Douglas Hall as the killer. Under the pressure of suspicion, Mr. Hall meets Jane Fuller at her hotel to ask more questions. The two develop a close relationship haunted by the sensation of "déjà vu", that they have met before. Douglas Hall learns nothing more that can help him. Ms. Fuller maintains that her father wanted her to help shut down the company. In spite of a developing romance with Hall, Jane Fuller does not reveal that she has consulted a lawyer and attempted to take control of the software company.
The police, faced with mounting evidence, eventually arrest Douglas Hall at his home and put him in jail. In a surprise move, Jane Fuller fabricates an alibi for Hall, saying they were both together the night of the murder. She helps Hall leave the jail. In spite of her assurances to him that he is not a killer, Douglas Hall succumbs to doubts, strongly suspecting himself as the murderer. He decides to enter the simulation once again to find the message Fuller left him.
Downloading into the body of John Ferguson, Hall awakens Fuller's virtual double, Mr. Grierson, at his home. Hall takes him to the club at the Beverly Wilshire and forces him to remember what he did with Fuller's message. At last, Grierson recalls that his counterpart gave a letter to Ashton, the bar tender.
A fight ensues, when Hall confronts Ashton about the message. Ashton had read the letter and kept it for himself. Using the information, the bar tender had discovered that his world was only a simulation. Ashton becomes distraught and dangerous following this revelation. He shares the information with Hall. Then he assaults Douglas Hall, shooting him and nearly drowning him in a swimming pool before he can be retrieved from the simulation by Whitney.
Douglas quickly recovers from the emotional and physical trauma of his assault in the virtual world. His experience with Ashton convinces him that the program is wrong and should be shut down. The content of Fuller's message also leaves him with doubts about the nature of his own world. Whitney, on the other hand, does not agree. He is not ready to give up 6 years of work on the project without even experiencing the simulation.
Returning to the hotel, Hall finds that Jane Fuller is no longer there. An equally perplexed Detective McBain is also in the hotel lobby. He tells Douglas Hall that his investigation revealed no such person as Jane Fuller, that Hannon Fuller had no daughter, after all.
Douglas Hall searches in vain for Jane Fuller, finding only a grocery clerk, Natasha Molinaro, who looks exactly like Ms. Fuller. Finally, Hall takes the ultimate test of reality following the steps that Ashton had outlined for him in the 1937 virtual world. He drives his car away from civilization, present day Los Angeles, stopping for nothing, crashing through barricades and
... he arrives at the end of the world. The carefully programmed setting dissolves into a colorless grid work.
Only after discovering this truth for himself, does Jane Fuller re-appear, downloading into her double, the grocery store clerk. Jane reveals that there are thousands of simulated worlds, one of which is the reality that Douglas Hall knows as his own world. The problem, however, is that Fuller and now Hall have become aware of the simulation. That is why Fuller was murdered.
What will happen to Douglas Hall, now that he knows he is only a cyber being in a simulated world? What will Whitney do, knowing that the program he worked 6 years to create may be shut down at any time? And what is behind the tearful and enigmatic Jane Fuller? Why hasn't she ended the simulation or terminated Douglas Hall? Finally, who really killed Hannon Fuller?
The answers to all of these questions may be found in the conclusion of The Thirteenth Floor . Enjoy!