Mizuki and her husband's childhood friend, Murakami, asks them to sign the witness section of the divorce papers. The loving couple hesitantly agrees, but Murakami, who has been separated from his wife and has been feeling sexual desire, ends up lusting after his friend's wife. Taking advantage of Mizuki's kindness, Murakami complains about the pain of being single. Mizuki is drawn to his sympathy, and before long...