Energetic and thrill-seeking sixth grader Toppa Bashin has his mind set on only one thing—the card game Battle Spirits. Bearing a ruby pendant inherited from his missing father, Bashin heads to school every day with excitement: not for academics, but for card battling, much to the chagrin of his peers.
One day, Bashin encounters J, the child prodigy champion of Battle Spirits, who bears a similar pendant. Star-struck, Bashin challenges J to a battle. However, the battle he gets is one he did not anticipate; the two are teleported to a mysterious arena in the sky—the Isekai World—where Spirits from the game become real.
