Kana and Masato, married for four years. They started seeing parts of each other they hadn't before, leading to more petty arguments... Around this time, Kana was invited to the home of Tsubasa, a classmate from their ● school days, whom she had reconnected with at a reunion. Tsubasa, who had been plain during their student days, was now strikingly beautiful... Soon after, Kana and Masato were both invited to Tsubasa's home and learned that the secret to Tsubasa's couple's harmony was wife-swapping.
