Kaoru married her coworker Ichiro in a late-in-life marriage. Ichiro has a hikkikomori son, Hanzo. Behind the remarriage was the need for someone to take care of Hanzo. As planned, Hanzo treats Kaoru as his real mother and lives spoiled. One day, Hanzou starts to plead with Kaoru that he wants a brother. Learning that Kaoru is nearing menopause, Hanzou becomes gripped by intense anxiety and finally takes action to impregnate her himself...
