Alan Bailey (Bruce Boxleitner), a programmer for ICOM writing a security program called Tron, finds his access is suddenly cut off by his boss, Dillinger (David Warner) and the Master Control Program (David Warner), which has taken control. Alan tells Lora (Cindy Morgan), who realizes that their friend Kevin Flynn (Jeff Bridges), a hacker and ex-ICOM employee, has been found out. The three get together to retrieve Flynn’s computer file that proves what Dillinger has done, but the Master Control Program activates a laser and digitizes Flynn, sucking him into the computer. Once inside, Flynn discovers an electronic world where programs are forced to compete in gladiatorial combat in the Game Grid or die. Even though Flynn is a User, not a program, Sark (David Warner) forces him to compete. Flynn meets Tron (Bruce Boxleitner), whom he recognizes as Alan’s security program. They decide to reach the I/O Tower to find out what Tron’s User, Alan, wants him to do. Avoiding the minions of the Master Control Program they fight their way to the tower, and then to the Master Control itself, where Flynn sacrifices himself so that Tron can put his instructions from Alan into play.