''Huh? He's been possessed by an incubus?'' The boyfriend of the devoted younger girlfriend, Usami Kyoka, suddenly becomes an incubus. Usually, one round is the limit for her boyfriend but even masturbating until the trash can is full... still has not sated his sexual desire. Seeing this, Kyoka decides to step up... ''Since I'm your girlfriend, I'll at least accept your sexual desire.'' Kyoka had some hope... but her incubus boyfriend's bottomless sexual desire pushes her past her limits and makes a mess...