When a man calling himself "the Scorpio Killer" menaces San Francisco, tough-as-nails Police Inspector "Dirty" Harry Callahan is assigned to track down the crazed psychopath.

High School student David Lightman has a talent for hacking. But while trying to hack into a computer system to play unreleased video games, he unwittingly taps into the Defense Department's war computer and initiates a confrontation of global proportions. Together with his girlfriend and a wizardly computer genius, David must race against time to outwit his opponent and prevent a nuclear Armageddon.