Sota Nishino Is A Good-looking High-school Student. He Meets Mai, Who Is His Friend Yukihiro Nanase`s Younger Sister. She Is Also A High-school Student And Somewhat Na Ve. Sota Nishino Mutters To Yukihiro Nanase, 8220 Your Sister Is Cute. 8221 Mai Overhears Sota`s Remark Through The Thin Wall Between Her Room And Her Brother`s.