 The narrator volunteers to beta test a new type of computer game for a programmer friend named Nathan.Called "Duke and Duchess" (though the title is changed to "God Game" at the end of the book), the game puts the player in the role of God for a small swords and sorcery world.However, after a violent lightning storm, the narrator discovers that the game's crude CGA graphics have become live video, and that he is now responsible for the inhabitants of a small, but very real, world somewhere else in space and time — a world that threatens to run away from his control and into total chaos.