Taiyo Asano is a super shy high school student and the only person he can talk to is his childhood friend, Mutsumi Yozakura. It turns out that Mutsumi is the daughter of the ultimate spy family. Even worse, Mutsumi is being harassed by her overprotective, nightmare of a brother, Kyoichiro. Taiyo will have to take drastic steps to save Mutsumi.