A loner in high school, Miyako is pulled into a (fake) relationship with school hottie, Koga-kun! It's actually for the purpose of hiding the existence of the alien possessing his body, Chiro-chan. But unlike the kind-hearted Chiro-chan, Miyako finds herself constantly butting heads with the more sinister, Koga-kun. But she begins to notice that, underneath that foul attitude, Koga-kun is devoting himself to helping her!