Manami, a married woman, accidentally sees her son's friend masturbating in the bathroom. Shocked by the sight of a man's penis for the first time in a long while, she finds herself unable to sleep. Left alone with the young man who's staying over, she finds herself drawn into his advances. Unable to resist as he treats her like a desirable woman despite her older age, she crosses the line. With her husband away on a work assignment, she's consumed by guilt yet can't let go of the young man's body. In this illicit affair, the married woman is overwhelmed by irresistible pleasure.