Rin, a mother who wants to raise her son Yoshiyuki to be an excellent lawyer like her late husband, is giving him a Spartan education. However, Yoshiyuki's grades are not improving and he is getting stressed out. Meanwhile, Rin herself is becoming more and more frustrated and is unable to help but masturbate... Rin is flustered when her son's friend Kenta sees her like this. However, the carnal desire that she had been suppressing with her reason finally explodes when she sees his hard, erect cock. And while scolding him, she starts to play with his erect cock...