The ten parallel realms connected to Earth are known as Worlds. At long last, the time to decide the Worlds' Number One has come!

Gao Mikado, a sixth-grader from Aibo Academy elementary division, has been chosen to represent Dragon World in the World Buddy Masters tournament. Guided by a messenger who claimed to be Saint Holy Sword Dragon, Gao went to Dragon World itself in search of his new Buddy! As if that was not an adventure enough, Gao interfered with the seal on an ancient shrine and released a forbidden monster! Known as the Demon Lord Dragon, Batzz, this forbidden monster had once devastated the continent of Dragon World. Batzz is a tyrannical monster which pays no heed to anyone. Yet, Gao believes he can become Buddies with even such a monster, and entered the tournament with him.

Ten representatives from ten Worlds.

One legendary Mirage Card that is bestowed to the winner.

An organization plotting for the legendary card, led by a man called Wisdom.

What will Gao, and his new buddy, Batzz get themselves into this time!?