Yamato Delgado is chosen to wield Cobalt Blade, the most powerful B-Daman, in a world where Old West flavor meets mysticism. B-Daman, a marble-shooting sport played since ancient times, draws many spectators, but only a few have what it takes to become B-Daplayers, and only one can be crowned B-Dachampion. Yamato must compete in B-Daman tournaments and defeat the villainous players of the Shadow Alliance. Along the way he befriends Gray, Bull and Terry, who join his B-Daman team. Mixing adventure and fantasy, the story centers on heated battles and the friendships Yamato builds through competition.