To go abroad on assignment, the daughter left home, and the mother, Ayano, started taking care of her stepson, Takao. Living with her stepson was sometimes enjoyable, but there were also times when she felt frustrated because she couldn't bring her boyfriend over. One day, while talking on the phone with her boyfriend for the first time in a long time, she got so excited that she started masturbating over the phone. Moreover, Takao happened to return home and caught a glimpse of this… Unable to control his own desires after seeing his stepmother's lewd behavior for the first time, Takao came up with a plan and put it into action to make her mature body his own.
