Due to the fatigue from housework, Yuu is suffering from severe lower back pain. One day, a friend of her husband comes to their home. The man is a freelance masseuse and immediately notices Yuu's back pain, which her husband hadn't realized. Concerned about the severity of her condition, he suggests a massage. Feeling guilty for not noticing, her husband also encourages her to receive the treatment. However, the man has ulterior motives towards Yuu. As he touches sensitive areas, increasing her pleasure, Yuu gradually succumbs to his advances...