Ichika's mother introduces her new boyfriend to her: her homeroom teacher, Riku. Ichika has Ichika a string of boyfriends, but in truth, she has always loved Riku. Ichika kisses Riku, who is passed out drunk at home. Although Riku knows he shouldn't make a move on Ichika, the daughter of his boyfriend and also his student, he is drawn to Ichika. Wanting to make Riku his own, Ichika uses reverse anal play to bring out Riku's true nature, teaching him that only she can accept it...