Manga about genius student who is promiscuous and starts a relationship with classmate after making a bet with him. They continue to have just a physical relationship and near the end of the story the classmates learns more about him such as how he is being used as a replacemtn for the cousin and how his parent are dead and his uncle is a powerful politician. Also, they make love at the protagonists house and the cousin catches them as they both come out of the shower. They are high schoolers.