Just an ordinary high school boy who loves big breasts—— Keita Tanaka, has his body possessed by "Nanika", a Fairy (?) who looks "flat-chested" but possesses overwhelming Power. From that day on, a Sniper belonging to a secret police organization—— "Kururu" (H-cup Goth Loli), a dual-gun wielder from a secret cult "Tsukune" (G-cup Twintail), and as a bonus, his childhood friend "Haruka" (F-cup Loli Kyonyuu), these busty Heroines begin to persistently involve themselves with Keita. Furthermore, Monsters (?) target Keita's life, and he gets dragged into a battle on a global scale——!