At the center of the world is a creature with the ability to grant any wishes. Yet, only one can arrive at the creature's home from the twenty-one invited.

Must be invited and arrived with others' invitation. They are plunged into the biggest tournament in the world to gather all the letter seals.

One such person involved is Robin, a young man whose adventure is a manifestation of his desire to prove himself to his parents. He's accompanied by George and his daughter. Their guide to the center of the world is Quinn, the great alchemist.

And the first thing on their way was a demonic invasion of a tyrants' land and his naïve queen.