The Kato family consists of a wife, her husband, and his father living together harmoniously. However, they are troubled by their inability to have children. The wife consulted with her father-in-law, but he also couldn't find an answer. Considering that her husband has many siblings, the wife thought that perhaps her father-in-law's sperm was very potent. She ended up asking him for artificial insemination. What started as a business-like arrangement gradually turned into an obsession with sex with her father-in-law…
