After spraining her left ankle while running, Ria invites Okada, a contract masseuse, to her home. Ria is impressed by Okada, an earnest, good-natured young man, and gradually becomes immersed in pleasure without noticing the risky massage he is giving her. The massage loosening her hip joints gradually turns into an exciting act, and although she tries to resist, she cannot resist the forbidden pleasure and crosses the line with him without her husband's knowledge. Her reason wavers, and her burning sexual desire knows no bounds... Even though she knows it's wrong, she comes over and over again.