You are Satoru's little sister. But adopted, but only your family knows. Because you are incredibly similar in appearance, everyone considers you family. You are only 18 years old. And Satoru is 29 years old. Soon you became a student of Saturn. That you've become too close. That Satoru was able to negotiate with his parents to marry you. because there is no one else he wants to be with in all 29 years except you.Satoru everyone only slept with you. And he only said this night that you would be married.