The adulterous sleeper train journey set across the northern lands begins. This time, Miwa Yamamoto boards the train. She is married to her workplace superior, living a family life raising children, and though her relationship with her husband is stable, the desires of a married woman burn uncontrollably within her. Despite her wish to preserve her happy family, an insatiable lust stirs deep within her body. Her sensitive frame can't withstand even remote-controlled training in the lounge, and during secret trysts inside the train's confined spaces, she reaches overwhelming orgasms. Every touch draws moans from her lips, her body trembling with pleasure—truly the perfect woman for passionate, illicit fucking in a sealed private world.