One day the player's character meets Dan Kuso, one of the Battle Brawlers, who teaches him the rules in a fight against Shuji. (you get a Serpenoid, a Juggernoid, and a Saurus that match the attribute you chose at the start of the game). After going to the local store and meeting Alice, who suggests the player should battle with other brawlers in the park to earn BP (Bakugan Points, the game's currency) a strange Bakugan called Leonidas falls from the sky, who is now the new best friend of the player. (Leonidas' attribute depends on what attribute you chose). Leonidas is an unknown and aggressive Bakugan that was created by all the hate and anger of the lost Bakugan trapped in the Doom Dimension. In several fights the player will meet a lot of people but at the same time a Darkus user, whose name is Marduk, decides to rule over all Bakugan together with Vladitor, another Bakugan that suddenly appears.
Right after Naga got the Silent Core, the seals that held Vladitor capti...