Whenever filming on location, a priest was always around to do a "purification ritual" before the start of filming. The priest would also hand out protective charms to the cast and crew to ensure their safety.
River Huang has admitted that he is sensitive to the presence of spirits in real life. He joked that whenever he had scenes with Wei-Ning Hsu, she would always posed him the question: "Do you feel anything?". The phrase became a staple of their conversations during the entire filming process.
The film is based on the Taiwanese folk-lore of mountain spirits that often incite people to become lost.
Wei-Ning Hsu had not watched horror films for almost ten years due to her fear of them. For this movie, the director requested her to watch them as part of the movie's preparation work. She ended up screaming through them.
Wei-Ning Hsu said she was really terrified during filming due to the makeup that the child actress was wearing. She ended up developing goosebumps all over her body, including on her face.