At a cocktail party to launch his latest creations, Adam and Eve, God is challenged to a bet by the Devil. The fallen angel, unimpressed by the boss's new toys, wagers that, far from becoming the custodians of Earth, humans will inevitably destroy themselves. God, alas, can't refuse such a wager in front of all his guests. If Satan wins, he gets his place back in Heaven and control of what little is left of Earth. If he loses, he will retire into outer darkness and never bother his ex-boss futher.
Coming down to Earth, we meet Martin Gray, a simple dentist at the end of his tether, who finds himself assisting the angel Gabriel in a desperate attempt to stop the Devil laying waste the Earth by means of a fiendishly cunning computer game. But when Martin's wife is kidnapped and dragged down to Hell, it is clear that the problems are just beginning...