Yuri Akiyama is 41 years old and lives with her husband and son. Her husband is in the prime of his working life and is often away on business trips, so he is not at home half the month. Since her son Akira failed his university entrance exams, he hardly ever leaves his room, and when he does, it is only once a week... he has become semi-reclusive. One day, while cleaning her son's room, she found an adult video with the shocking title "Incest." At that moment, she felt someone looking at her, and when she turned around, her son was standing there.