Minato Hisaya, a normal high school student, has a female friend who is a bit peculiar. She is Aoi Hatsuki, the most beautiful girl in the high school. For some reason, they get along very well, and since they happen to live on the same floor, they gradually become good friends, coming and going from each other's houses.

One day, Minato suddenly asks her to show him her panties. At first, Hatsuki is reluctant, but then she starts to roll up her skirt?