A "reenactment" with his mother turns into "forbidden real sex"! One day, the peaceful Aoyama family is shocked when their only son, Keita, impregnates his girlfriend. "How could that honest boy have done this...?" Aina, the mother, questions Keita, trying to interrogate him about the whole story. However, Aina, filled with a mixture of jealousy and frustration, ends up guiding her son's penis into her vagina during the act reenactment! And then she crosses the line...