Seijyun High is located on a small island in the middle of a lake on the outskirts of Aoharu. Under the financial aid of a certain zaibatsu, its motto is "to raise women who display feminine virtues and the time-honored traditions of Japan within themselves". Student statistics are mostly unknown but almost all of them come from well off families. The vast majority of its students live in the scenic campus dorms.
Seijyun is often criticized as being too old fashioned with students only being allowed to leave during summer and winter vacations as well as New Years'. Any other student leave requires express permission from the principal.
A well-kept secret surrounding the school regards its underground all-female gang who use force and subterfuge in order to gain freedoms they wouldn't have otherwise. Despite this, the school maintains its overtly conservative image.