Tron (1982)

Hacker/arcade owner Kevin Flynn is desperate to prove that the hottest videogames from ENCOM were stolen from him by a former co-worker, who is now a senior executive there. Flynn's efforts, however, are made fruitless by ENCOM's "Big Brother," the megalomaniacal Master Control Program. One night, the MCP catches Flynn in an attempted hack and pulls him into the virtual world. Flynn finds that the MCP is making life in the virtual world just as, if not more, miserable as in the real world. Flynn's only hope is to find TRON, a heroic independent system security program, and help him destroy the MCP to bring order to both worlds.