A forty-something woman named Rieko Kobayashi struggles daily with her unyielding sexual desires, even though she believes they should have calmed down by now. She often releases these urges through infidelity fantasies involving her daughter's boyfriend, Shouji, without realizing how out of control her lust has become... Eventually, Rieko manages to join her daughters on a hot spring trip despite their objections. In this erotic setting, she boldly seduces Shouji behind their backs, hoping to make him hers. As he succumbs time and again to the allure of her mature charms, both parties find themselves unable to resist the temptation that lies before them.

四十路を越え、性欲も落ち着くかと思いきや、里枝子は身体の奥底から沸き上がる火照りに日々悩んでいた。しかもいつも娘の彼氏・晃司との不貞妄想で発散させており、その欲望は留まる事を知らずとうとう…。その後、娘たちの温泉旅行へ強引に参加した里枝子。性欲に溺れる彼女は、旅先で彼を自分のモノにしようと娘の目を盗んで大胆に誘惑する。そして大人の女が魅せる痴態に心惹かれた晃司は、幾度も…。