Tooru Kouno's attractive appearance draws unexpected attention on his first day at an all-boys school. Having to transfer to a school without girls has been bad enough, but adding to his list of frustrations are boys staring at him all day long. However, he hopes that there may be girls around, since he ran into a lovely pink-haired girl on campus earlier that day. After being escorted to his dorm by his classmate, Yuujirou Shihoudani, he meets a student named Mikoto Yutaka, who looks eerily similar to the girl he saw previously. To his shock, he realizes Mikoto is the girl and confronts him about this revelation. Yuujirou divulges that he and Mikoto crossdress as part of their job: a school tradition in which attractive first years are chosen as idols called "Princesses" in order to boost the morale of the students—and because of his looks, Tooru has been chosen by the student council as their third Princess! The boy-school Tooru transferred has a strange system. A student who is chosen as Hime (princess) must be disguised in woman's clothes at every opportunity in order to add beauty to manly life. Tooru is selected as the candidates for Hime. At first, he refuses, but knowing that Hime has various privileges, he makes up his mind to become it.