Welcome to Paradigm City, a strange place in the not-too-distant future. The citizens of Paradigm City have lost their collective memory, the result of a mysterious event that occurred many years ago. Although Paradigm City has not fully recovered from this catastrophe, its residents have used their natural human intuition to recall the uses of electricity, automobiles, and other modern conveniences. Millionaire playboy Roger Smith uses the help of his giant robot, The Big O, to protect the people of Paradigm City from evildoers.