The Shinmura family, consisting of a wife, her husband, and his father, live harmoniously. However, they are troubled by their inability to have children. The wife consulted with her father-in-law, but he was also at a loss. Since the husband has many brothers, the wife thought that perhaps her father-in-law's sperm was very potent, so she asked him for artificial insemination. What started as a business-like arrangement gradually turned into an obsession with sex with her father-in-law…
