A grown son suddenly becomes a hikikomori. Chika, who takes care of her son who has withdrawn into his room and lives like an empty shell, tries to help him reintegrate into society step by step. However, her son's actions gradually escalate. Chika, who is not satisfied with her sexual life with her husband, slightly forgives her son, who then dares to seek even his mom's vagina. Knowing it's wrong, she shows her excessive affection by accepting it, overwhelmed by her son's cuteness.