Wataru has recently noticed that he is beginning to be more attracted to the beauty and sex appeal of his girlfriend of two years, Kyoko's mother. Meanwhile, Kyoko has been feeling a bit sexually frustrated ever since her divorce from her husband, and while she smiles at the sight of her daughter and Wataru getting cozy with each other, she also feels a Kokoro envious deep down inside... One day, when Kyoko gets out of the bath, she witnesses Wataru looking through her underwear in the dressing room. Staring at the completely naked Kyoko, Wataru panics and runs away. From that day onwards, a lewd love triangle full of immoral excitement begins...