Yoshio's friends come to his house to study. The target of their attention is Yoshio's beautiful mother, Ayumi. In between studying, they sneak a peek at Ayumi's body. At that time, one of his friends, whose mother is not around, ends up staying at his house to look after her... Ayumi is begged by the boy while they are alone in the room, and they end up in an inappropriate relationship. Although she feels guilty, she can't stop her body from throbbing...