Kayo is happy that her son's best friend, Kenta, is staying over for the first time in a long time. She was worried about her son's relationships at school, but it seems like her worries were unfounded. However, her relief is short-lived as the sexual desires she has been suppressing in order to be a good mother begin to bubble up. She indulges in masturbation with the utmost care so that her son and Kenta don't find out, but Kenta happens to stop by the bathroom and sees her in a lewd state...