Mako is a married woman who has been married for four years. One day, her husband brings his young subordinate, Shoji, to their house. He misses the last train and lets her stay the night. When he opens the door to go to the bathroom, he sees Mako in her underwear. "He's watching me... I'm a mean guy who wants to trouble him because he seems so simple..." Shoji's desire is uncontrollable, and that night he sneaks into her futon and demands her body. From that day on, the two of them fall into a life of intimate sex, sweating and craving each other's dicks in close proximity to their husband...