While her husband was away on a long-term assignment, Fumiko could no longer endure the loneliness and began a relationship with her only son, Tatsuya. Despite knowing it was wrong, she couldn't resist the pleasure and continued this way. When her husband's assignment neared its end, Fumiko had no choice but to put an end to the sordid relationship. She unilaterally announced the break-up to Tatsuya. However, her body hadn't forgotten Tatsuya's touch. "Mom, can you really forget my dick?" Those words began to shake Fumiko's resolve.