Shunta Mogami loves the Battle Spirits card game, until a light from one of his cards carries him off to Spirits World, the place where all Battle Spirits began. There he meets Eto, a girl who says she brought him over to save Spirits World from ruin. The Evil God-King, who once schemed to destroy that world before being beaten and sealed away, has returned. Joined by Yoku Albatrosa, a self-assured player with a green deck who also comes from another world, Shunta sets out to track down the twelve God-Kings whose power first sealed the Evil God-King. The result is an action fantasy adventure built around card battles.