Three years have passed by since the Brawlers defeated Naga and bid farewell to the Bakugan. Drago sacrificed his physical body to become the new Perfect Core, uniting the Bakugan's fractured homeworld and forming New Vestroia. However, aliens arrive on New Vestroia, and begin colonizing the Bakugan's home, unaware that the Bakugan are intelligent beings. The Bakugan are returned to their primitive ball forms. Upon the defeat of Tigrerra, the last of the Fighting Bakugan of the Battle Brawlers, Drago is freed from his role as the Core of Vestroia and seeks the help of Dan once again to help save his world.