A housewife named Shiokawa Umi (lit. Cloudy Tendon) lives an ordinary life with her husband. However, she isn't satisfied with their sexual relationship and repeatedly masturbates using rope. One day, her husband brings home a new employee he met at work. This middle-aged man had just retired from his previous job before joining the company. He accidentally witnesses Umi's self-pleasuring act and then forces himself on her. Surprisingly, Umi doesn't seem too upset about it and even begs him to continue assaulting her in the future...