"Tenma Matsukaze is the oldest son of the royal family, and as the first born, he will also be the future king of the kingdom. But his true dream is to explore the world with all his facets, traditions and secrets, he keeps a big map hung on one of the walls of his bedroom, dreaming of going in every place he knows and doesn't. Of course he also loves his kingdom and all his peasants, even the poorest ones, and he always tries to help them by giving them food and money. He also has a trusted friend named Kyousuke Tsurugi, son of the most trusted soldier of the royal family Ishido Tsurugi, who's training to become a soldier just like his father, so that he can protect his beloved friend. Kyousuke and Tenma are both really close to each other, so much that the kingdom calls them "nonblood brothers", and exactly for their close relationship that their feelings will change, by becoming something else..."