Upon learning that her son Ryota's classmate Kazuya is a single parent, Tsubaki's mother sympathizes with him and becomes sympathetic towards him. However, Kazuya, a bully, is attracted to her beauty, and the moment they are alone... Tsubaki feels guilty about having had a physical relationship with her son's classmate, even though it was out of her control. However, Kazuya takes this opportunity to continue to torture her mercilessly wherever he goes. And her body, which has been toyed with by the young man's sexual desire, eventually becomes unable to suppress the throbbing in her groin...