A father who is devoted to his work and does not care about his family. His mother Yuri and her only son Shinya have lived together as if they were a single-parent family. However, recently, perhaps as a teenager, Shinya's attitude towards his mother has suddenly become colder. Yuri feels an indescribable loneliness as Shinya becomes more independent from his parents. At that time, Shinya tells Yuri that he is leaving home, and Yuri feels a sudden surge of loneliness. Not wanting to lose the only person who supports Kokoro, she clings to Shinya...