The story of Bakugan: Battle Brawlers revolves around a set of metallic cards that mysteriously fall from space. On finding them, kids from around the planet discover that the cards also provide access to a variety of monsters that can be pitted against each other and so develop a game based on the cards and monsters and set up tournaments. One group of these kids, who name themselves the "Bakugan Battle Brawlers" and who are led by Dan, find that the cards also serve as a link to a parallel dimension known as Vestroia. Here they discover that the game and its monsters that they are dedicated to mastering is tied to an imbalance of positive and negative energy in Vestroia. This imbalance must be corrected to avoid unspeakable consequences for Vestroia, and since a link has been made to the Earth, eventually the kids' home as well.
