Not in This World (2019)

Jeong-chul, a mountain hermit, is drawn out of his solitary existence by the sound of Ji-su singing in an empty town square. He follows and befriends the teenaged girl, a fellow stubborn outsider in a cruel world. After falling out with her family, Ji-su runs off and joins the underworld, while Jeong-chul tries his hardest to save her from destroying herself.