Three years into her marriage to Osamu, a man working at a securities firm in Tokyo, he suddenly announced his desire to become a day trader and decided to change careers. Citing that the countryside would be quieter and better for gathering information, they moved to his rural hometown. There, Mako meets her brother-in-law, Kyoji, for the first time. Unlike Osamu, Kyoji is rugged, strong, and powerfully built, and Mako falls for him at first sight. Drawn irresistibly to his presence, her heart begins to shift toward him, while Kyoji, in turn, finds himself captivated by Mako's big tits. Gradually, their relationship deepens.