A married couple, the Sawamuras, live in a luxurious apartment located in the heart of the city. The husband still remembers vividly how intensely he had sex with his wife Reiko last night. Reiko was insatiable, refusing to stop the sexual act until semen was finally released. Meanwhile, the husband has recently noticed a clear decrease in his sperm volume. Despite this, Reiko has always supported him and treated him with devotion. However, she harbored a significant secret she could not reveal to her husband.