High School student David Lightman (Matthew Broderick) 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 (Ally Sheedy) and a wizardly computer genius (John Wood), David must race against time to outwit his opponent...and prevent a nuclear Armageddon.