A couple visits a hot spring inn, and after relaxing in the open-air bath, they decide to receive a massage service from the innkeeper... As the beautiful mature woman is gradually caressed all over her body, sweet sighs begin to escape her lips. Despite her initial resistance, as her sensitive groin and breasts are massaged and she becomes covered in oil, she succumbs to pleasure in secret from her husband! In this erotic world of rope bondage she has never experienced before, she realizes she is a masochist and becomes addicted to this abnormal sex...