Through an unexpected turn of events, an ordinary elementary school student, Hiro Enryu, finds himself in the world of the "Dragon Collection" game. This is a world called Dragon Earth, where gods, humans, and monsters exist side by side. Those who roam this world using a magic book, called a Grimoire, and cards to summon monsters and search for treasures that bear the powers of dragons are called Dracolle Battlers. Despite his bewilderment, Hiro becomes a Dracolle Battler and, together with the friends he meets there, begins his adventure to become a legendary Dragon Master!