Kouta Ichinose is en route to his grandfather's academy, but his knowledge of it is limited to the fact that most of the students are female. This piques his interest and leads him to expect a romantic harem-like experience. However, when he gets lost on his journey to the isolated campus, he discovers that his grandfather kept many crucial details from him. In reality, the academy is a prestigious school for girls, focused on mastering the art of ninjutsu!