I ended up having a relationship with my stepson because I was forced. It happened just as Reiko, who realized that she was interfering with her daughter's couple's child-rearing, offered to end their cohabitation. Her daughter opposes it, not wanting to make Reiko feel lonely, but Reiko knew that if she continued to live together, she wouldn't be able to refuse her stepson because she was starved for a man. But she can't ignore her daughter's kindness... Reiko will live a tightrope cohabitation life, connecting with her stepson as a woman while wishing for her daughter's happiness as a mother.