Shunta Mogami is fond of the Battle Spirits game. One day, a light emanating from a Battle Spirits card transports him to Spirits World, the source of all Battle Spirits. There, he encounters a girl named Eto, who asserts that she summoned him to Spirits World to stop its destruction by the revived Evil God-King. This entity had previously plotted to destroy Spirits World before being defeated and sealed away. Alongside Yoku Albatrosa, a confident user of the green deck who also arrived from another world, Shunta embarks on a quest to locate the twelve God-Kings whose power originally sealed the Evil God-King.