Chisato Shoda's ryokan hosts her daughter's husband and his parents. Originally, her daughter was supposed to come too, but she had to cancel last minute. Chisato was asked by her daughter to "please take good care of my husband and grandfather," and those words made her heart race. She ends up peeping at her daughter's husband masturbating in his room, causing her own arousal to surge uncontrollably, left frustrated and unsatisfied. Unable to suppress her desire, she indulges in a forbidden taste. Eventually, her lust erupts—Chisato advances on her father-in-law, leading to both father and son submitting to her carnal hospitality.