The tutor's older sister is an excellent tutor who has improved the grades of many students. However, in fact, I like Shi-Takon and Ko-Mo. I proceed with the lesson while hiding such a propensity, but I am at the mercy of the mischief of "Hajime-kun" who is a masochist. And finally, reason is puttsun! The older sister whose self-control has collapsed transforms into erotic.