Yuko lives with her daughter while her husband goes on a business trip. She felt extremely lonely when she wasn't with her husband, but it didn't seem like she was alone. Toru, her son-in-law also often has to masturbate in the middle of the night. Yuko knew how frustrating it would be to have an unfulfilled libido. Her daughter's responsibility was also her responsibility, so she had to help Toru release all his long-accumulated sexual desires.