In country A, I receive three letters every day, no sender, no address, just a little grimace, and the next day after receiving the letter, someone dies, and the crime scene is exactly the same as the photo in the letter. Wu Jian, an elite criminal police officer, and I searched in many ways and targeted the suspect at the "haunted house" on Khao San Road. However, in the haunted house, we encounter unclean things, and in the process, new murders occur.