During summer vacation, Hotaru, a young girl visiting her grandfather's house, wanders into the “Forest of the Mountain God,” a place believed to be inhabited by spirits. After getting lost and frightened, she is rescued by Gin, a mysterious boy wearing a fox mask. Gin helps her find her way, but warns her that he cannot touch humans nor be touched by them, otherwise he would disappear forever. Although neither fully human nor a spirit, he continues to wait for her. From then on, she visits him every summer, and over time their bond grows stronger, even though they can never truly touch.