A mother named Emi raises her son alone after divorce, and when he graduates and moves out to start living by himself, she feels lonely. To create some memories together before he leaves home forever, they decide to go on a hot spring trip. While changing into yukatas (casual summer kimonos), Emi asks her son for help, unaware that his face is buried deep between her large breasts. Suddenly, he confesses his love for her, leaving both shocked but intrigued. Despite being a mother figure, Emi still desires intimacy; thus begins their taboo journey filled with incestuous pleasure as they explore each other's bodies during their vacation getaway.
