The main character, Keisuke Oda, is a very ordinary college student. His parents are busy on business trips and live with almost two of his sister-in-law, Mio (big breasts), who is a teacher at the school. Her first experience was robbed while she was being tutored by her sister-in-law, and since then she has not been able to raise her head and has been treated like a pashiri. However, thanks to that, ironically, the hero who grew up well. He is looking for a part-time tutor on a bulletin board in a city park, but he hasn't seen any hope for students. ――One day, while her sister-in-law was away, her sister-in-law's student, Ayano Kobayakawa, was before the test, so she asked me to teach her what she was studying. Although her sister-in-law refuses to be her absence, the hero who couldn't see her crying to teach her study is her study as her temporary tutor To see. However, when she climbs into her house, instead of studying her, she asks only about her hero, digging roots and digging leaves. When her stunned protagonist asked why she was interested in me, she told her students at the school that her sister-in-law's style was good because her younger brother was rubbing her every day. It was that there was! With the surprised protagonist in the back, she began to expose her breasts when she was seriously worried! The hero who gets excited while rubbing her breasts. But that was the same for Ayano. Ayano lying on the bed couldn't hide her excitement while saying, If you know a man, it's more ...!? A few days later, the protagonist spends her time chilling her sister-in-law asking her to get rid of her, but when she succeeds in bust-up, she comes back with her friends! Since then, various girls have been rubbed by the hero and entangled in SEX, and her sister-in-law also got caught up in a fuss! Even so, girls who want to be students appear who heard the rumors of her bust-up, knowing or not knowing the hardships of the hero! What will happen to the hero? And will their desperate desire for bust-up be fulfilled !?