Sanshiro's prospects for an adventure are practically non-existent in his small island hometown, until the day a mysterious stranger invites him to play a game... Without warning, Sanshiro is transported to a reversed universe to play BakéGyamon—a game that pits monsters against monsters. Along the way, he meets other players who have a specific reason for being there: to obtain the wish granted to the winner. But how far can Sanshiro get when the monsters he's been paired with are just a bunch of little mud balls?!