Senior school student David Lightman (Matthew Broderick) has a knack for hacking. However, while attempting to hack into a computer system to play video games, he taps into the Defense Department's war game and also initiates a bang with global proportions! With his girlfriend (Ally Sheedy) and a wizardly computer guru (John Wood), David has to race against time to outwit his competitor. . .and avert a nuclear Armageddon.