The Loner

Su Na, once a bright and adorable girl, locks herself alone in her room after her best friend’s Self-harm. She starts to talk and behave as if someone else exists in her room, but never opens the door to anyone. Finally, her uncle brings his fiance, Yun Mi, a psychologist specializing in hikikomori (people who isolate themselves from society), and she finds Su Na’s trouble has something to do with the family’s secret history.