Sanshirou is always itching to go on a new adventure, much to his mother's dismay. One day after class, he boards a ship, determined to travel throughout Japan. However, after a freak storm batters the boat and the boy is thrown overboard, a strange man appears and asks if he'd like to play a special game called Pandemonium. In a flash, Sanshirou is transported to a strange place filled with monsters, special cards called Gekifu, and danger at every turn. Alongside his new mysterious companion Fue, Sanshirou must battle against others in an attempt to become the greatest Gekifu player of all – but just what is this game, and what does Fue have to benefit from it?