A father-in-law falls in love with his son's wife, Nanako, someone he absolutely should not be interested in. Nanako has a wonderful smile and a charming, slender body. Even though he knows it's wrong, he can't help but fantasize about his son's wife in lewd situations. A daughter-in-law masturbating as if to show off, a daughter-in-law gently giving him a blowjob in the bath... and the father-in-law's delusions continue to grow...