After several years of marriage, the Shiraki couple enjoyed a peaceful and happy life—until one day, a new neighbor suddenly moved in next door: Kawai, a ronin student preparing for college entrance exams. Kawai instantly fell in love with Yuko and confessed his feelings directly to her. Though she rejected him, everything changed when a strange odor began emanating from Kawai's house, followed by signs of a potential fire. Rushing over in panic, Yuko found Kawai collapsed and unconscious. His weak, heartfelt words upon waking deeply moved her. From that moment on, Yuko began leaving false notes for her husband and made the fateful decision to go to Kawai's side.