Dillinger, the powerfull President of Encom, a computer programming development company, has developed an application named MCP (Master Control Program). thanks to this software, he can rule over the computer system of Encom that shelters creations of the people developping for the trust.
When Alan Bradley sees his access refused to his last software Tron, a computer application destined for securising programs by bypassing the MCP, he calls for Flynn and Lora's help. Flynn was formerly a developper for Encom. But his game « Space Paranoïds » was stolen by Dillinger who now takes the juicy benefits out of it. Flynn wants to penetrate the system because somewhere leaves the proof that Dillinger did appropriate his programs.
To make this, he must access to the central computer and reinit Tron by using a machine at Encom's. With the help of Lora, a scientist that undertakes researches on disintegration and reorganization of molecules for the account of the computer company, Flynn and Alan penetrate in the enterprise.
On the way to penetrate the MCP, Flynn is disintegrated by Lora's powerful research laser. He is instantaneously transported in the microships of the central computer of Encom. He resumes conscience in an other dimension, the electronic world dominated by the MCP where programs of the computer have taken the appearance of inventors, their human creators.
Flynn, who became Clu, is condemnee to perish by the game. He has to face the deadly games of Sark's warriors, the administrator of the MCP who has the appearance of Dillinger. Flynn gets escape in company of two other programs; Ram and Tron, double of Alan, on electronic motorbikes. Taken in hunting by a tank program, they have to separate. Deadly injured, Ram will succumb only after having understood that Flynn is a creator; to his eyes, a god.
Tron directs to the communication tour so as to attempt to contact his creator. he meets her friend Yori, the double of Lora. Together, they must face the Cerberos, the guardian of the communication tower. The former, a program to the effigy of the professor Walter Gibbs, the associate of Lora who has to pay Dillinger back, authorises them to enter. Tron then enters in communication with Alan who records on his disc the informations that have to be installed in the heart of the MCP so as to destroy it. Followed by Sark and his men, they embark on a solar sailboat program with Flynn who came to join them again…
Spoiler ! the end of the story is revealed below…
Together they arrive in front of the MCP where Tron has to face Sark. While Tron persists to place the disc in the MCP's heart, Flynn dives in its beam of energy. He thus diverts the attention of the MCP and allows Tron to insert his coded disc. While Flynn rematerializes in our world, accesses to all programs held by the MCP are liberated. The destruction of the MCP announces the end of Dillinger. Flynn finds back his rights on his games and takes Encom's presidency.