Wife Ageha discovers an unnatural amount of SM gear hidden in her husband's room. Shocked, she confides in her trusted friend Misaki and asks her to tail her husband. During the surveillance, they encounter a woman named Amami whom her husband has been keeping imprisoned. As the secret is exposed, tension mounts between the two women—only to be met with even more intense BDSM training. At a hidden location, their relationship begins to shift, leading them toward an even greater trial.