After purchasing a house in Tokyo, Haruna and Kohei decide to invite Kohei's father, Michio, who had been living alone in the countryside, to stay at their new home. Haruna diligently takes care of her father-in-law during his short visit. Seeing her devoted actions, Michio gradually begins to develop lewd fantasies about her. Unable to suppress his desires any longer, his feelings finally reach a breaking point...