Mihori, a slender young wife living peacefully with her older husband. Her brother-in-law, a photographer, returns from overseas after a long time and stays with them for a week. By a small chance, Mihori becomes a model for a photo shoot. As the photos are being taken, a suspicious atmosphere arises and she is tied up for the shoot. At night, she sneaks out of bed and ties herself up for a solo masturbation session. Her brother-in-law catches her and subjects her to bondage training. Excited by the thrill and pleasure, she is trained in bondage in her husband's blind spot. Mihori, who has become a captive of the ropes, gradually becomes her brother-in-law's slave.