Shun Asanaga is a 15-year-old junior high school student who has an optimistic and bright personality. One day, he discovers a mysterious crystal in the office of his father, a scientist and businessman. Upon touching it, the world becomes distorted, sending Shun into the world of Endra. Emilio, a prince of the kingdom of Endra, is approaching his 16th birthday and despises the reigning king, Delzain. Since Emilio has now reached the age at which he can inherit the throne, he takes up a weapon and attempts revenge. However, because Emilio is too weak, he is captured by Delzain and imprisoned. While Emilio is in grief, the wall of his cell becomes distorted, and Shun appears from it with two goals: to return to his own world and to complete Emilio's revenge. What future lies ahead for the two boys trying to survive in Endra, yet raised in two different worlds?