The story revolves around Kevin Flynn a former employee of Encom and now host of his own arcade. He's mad because Ed Dillanger, a sneaky rival, stole his idea for a series of video games that would have moved him up the corporate ladder. Since then he's been trying to hack Encom in order to find evidence of said crimes. However Dillanger is on to his plan and his friends Alan Bradley and Lora warn him. Bradley himself is ticked off on account of him now not allowed to develop his security program Trace-ON-JA-307020 or TRON for short. So they devise a plan to use TRON as a means to destroy Master Control Program, (An A.I. that controls Encoms Mainframe and has plans for global domination.) and get the evidence. Flynn hacks into the mainframe long enough for Alan to activate TRON, however MCP catches on and uses an experimental teleporting laser to take Flynn into the digital world. It works and he finds himself in a world where each computer progam in Encom is represented by the person that created it. In TRON's case he looks exactly like his creator Alan, or Alan-One as he refers him as. TRON, Flynn and RAM an insurance program break out of the Game Grid to seek the means to destroy MCP.
Legacy takes place 20 years after the first movie. Sam Flynn, Kevin's Son finds a lead on his missing father through his old arcade. He is also zapped by the teleporter which takes him into the new and improved Grid. Inside he must find his father and with the help of Quorra, a program with a mysterious past must battle Clu, a program made in Flynn's image gone rogue, and escape.
Now for the main event folks, Could It Exist In Real Life?
I already gotten through the theoretical pros and cons with Teleportation in my Power Rangers Analysis, so no need to go there again. However it does solve the problem I mentioned. See the Laser uses a twin beam system, one beam hits the object while the other takes it apart and converts it into data. In the case of Flynn the beam kept him frozen in suspended animation. If one were to freeze a subject into that state on a cellular level it would prevent the cells in the body from reproducing temporarily so that the subject may be safely teleported away to their intended destination. However it's only a theory.
Now for the other stuff. The first is the Identity disc. We all heard the line "Everything you do or learn shall be imprinted on this disk." While the disc is mostly meant for you to have a memory card, it also doubles as a weapon designed to delete the program fighting you. While something like it is not real the concept behind it is. For starters we think of Hard Drives for they record everything we make from programs to word processing files. However now a days we think of Flash Drives which is the same thing only portable. Flash Drives make more sense, since each Program in the series has one disc and most real life computer programs can be activated automatically by putting the FD in the computer rather than the classic double click As for using it as a weapon....very unlikely. Sure throwing a flash drive at someone would hurt like hell, but it wouldn't delete them. The original disc was based off the Discus a weapon used in ancient Greece which started out as an Olympic throwing sport, while the Newer Ring looking disc is based off of the Indian Chakram and the Chinese wind and fire wheels. The former based on their throw technique and the latter for their use in melee abilities. However because of the aerodynamic design, neither of the three return to the thrower.
The second is the energy, a liquid in the world of TRON which serves as both a power source to the world as well as food for the inhabiting progams, along with the visiting users. This can exist ladies in gentlemen. According to HowStuffWorks, there are at least 10 known biofuel sources. Biofuel being fuel sources taking from everyday edibles from Corn, to Soybeans and even Water. Hard to believe the stuff that fuels you can fuel the world huh?
The third is Programs and Users. Users do exist, they are just regular humans with computer and internet access. As for programs that's a mixed bag. The main program characters portrayed in the series have the faces of their creators. TRON and Clu have Alan and Kevin's faces respectively. Clu was originally designed for hacking but later became the head program of the grid a title originally owned by MCP. And Tron is essentially an Antivirus Program. In fact Norton a popular Antivirus product once claimed that their product was based off of Tron. However each program having a voice and mind of its own make us wonder if they are more than just an ordinary program. Many fans debated that TRON and Clu are A.I. or Aritficial Intelligences. Programs and to an extent whole computers designed to think like us. Can they exist? Yes and no. True A.I. is a dream all computer nerds have, however while it is not impossible. You would have to be a pretty good computer technician to come up with one that doesn't turn against you like Clu or MCP. As for the Users ability to change things that's easy to explain. They have the power in there, because they have it in the real world. The only difference is in the real world it takes keystrokes while on the grid it's your hands.
UPDATE: According to Youtuber Ukrainegame, There was a behind the scenes featurette in which stated that professors of CalTech have been consulted on the possibilities of most of the stuff happening in Legacy to be true. That it could be theoretically possible to take a computer program and bring it out into the real world in the flesh. When he told me about that I was actually pretty terrified. Don't get me wrong I am awed at the possibility, but still it's like Ian Malcom said "I hate being right all the time."