It has been four years since Nakajima Chisato married her husband Hideo. It was Chisato's second marriage and Hideo's first. When they first got married, they lived with Hideo's father, but he passed away last year, and now they live together. Chisato hopes to have a child with Hideo, and Hideo himself is quite into that sort of thing, so the couple have sex every morning and every night. Their relationship was going smoothly, and they lived a harmonious life together, until one day, Hideo invited a man named Minegishi over to their house. Minegishi Saburo... He was Chisato's previous husband.