Yumi's relationship with her son began about six months ago when he caught her masturbating. She was forcefully overpowered, and since then, she has repeatedly engaged in incest at her son's demands. However, Yumi began to fear that "her son would become ruined" and resolved to end the relationship. But it was too late to turn back. When she announced the end of their affair, her son's attitude changed drastically, treating her coldly. Exhausted by these harsh days, Yumi ultimately chose to return to her son on her own.