One day, the heir to the prosperous Kaburagi Corporation, a soft-spoken yet cultured young man, received a visit from his family lawyer. He came to pass on the final wish of the boy's late grandfather: that he attend an all-girls school!

With his childhood friend Mariya - a talented fashionista - to help him with the "transition," Mizuho enrolls in his new school. It's not long before a series of strange misunderstandings leads to him being elected the school's "Elder Sister," the idol of the entire student body!

It's one wild event after another at this all-girls charm school! Can Mizuho make it through the year with his identity - and his dignity - intact?