Matsunuma Jin is a middle-aged teacher who has recently divorced from his wife. On a normal day, he received a mail from one of his students, Rebecca. In the mail, there was a picture of a pussy, and a message saying "Come to the old school's infirmary and I'll give you this girl's virginity♪"?! When he reached the infirmary, he found his class's president, Sayoko, waiting for him alongside Rebecca. There, he crossed the line between a student and a teacher as he was confined to the infirmary and was forced to verify his and Sayoko's relationship by having sex with her. After that, he found out that Rebecca is actually the leader of a committee called "Sex Research Committee", also known as "Sekken-bu", which helps and supports both men and women facing sexual troubles. In fact, Rebecca called him to the infirmary because she knew that Matsunuma had recently divorced and was in need of sex. Not only is Sayoko filled with the pleasure, Rebecca wants to get "closer" to Matsunuma. In order to do that, the three of them start practicing having sex in the infirmary, and to understand their bodies' deeper compatibility...