Caladria is a futuristic planet with five countries: Dreilune, Tamarin, Nephrine, Werethia and Caeldori. Each country has its own individual features, some were inspired by Earth as time went on. Nerisu Himenomiya, the princess of Dreilune, lives her everyday life with her childhood friends as she attends high school. Sooner or later, her childhood friends, the Otori twins, get kidnapped and it turns out Nephrine has plans that involve the whole world...