Dan Kuso's life changed one day when cards fell out of the sky, which he and his friend Shun used to invent a game called Bakugan. With other friends, they form a group called the Bakugan Battle Brawlers, and then are accidentally dragged into fighting for the fate of Vestroia (the Bakugan's home dimension). Dan and the brawlers decided to bring back balance by meeting new friends and allies in the other worlds, learn more about the origin of the Bakugan; and facing Naga.