Two years ago, Ayaka lost her husband and has been living with her daughter ever since. Her grown-up daughter got married three months ago but still lives together with her new husband, making them all live under one roof. There was something bothering Ayaka. She had developed a habit of peeking at her daughter and son-in-law's intimate moments just to comfort herself. Back then, she was only allowed missionary position because that's what her husband preferred. Their intimacy seemed so foreign to her. One day, Ayaka was caught masturbating by her son-in-law...

二年前に夫を亡くし、それからは娘と二人で暮らしてきたあや。社会人の娘は三ヶ月前に結婚したが、その後も夫婦で同居して、今は娘夫婦と三人で暮らしていた。あやには困っていることがあった。娘夫婦の営みを覗いては自分を慰めるというクセがついてしまったこと。かつては夫婦の営みは、はしたないからと正常位しか許されなかった。そんな営みしか知らなかったあやには娘夫婦の営みが衝撃的だった。ある日、あやは自慰を娘婿に見つかってしまい…