The story begins with a letter. I am a postman in a remote county town, and one day my director hands me an old leather-made special letter that needs to be delivered to a place called Beigou Village. Before setting out, I heard many rumors about the village from my colleagues, among which the most shocking was that no one had ever left Beigou Village alive. To keep my job, I had to deliver this letter with a stiff upper lip. At this time, my closest colleague, Lao Cong, kindly gave me his father's only heirloom as a protective charm for my journey. It turned out that his father had experienced a thrilling adventure in search of treasure and had narrowly escaped death several times, entering the precipice and unexpectedly finding a small stone. Who would have thought that this unassuming stone saved his life during a supernatural event? I put the stone in my pocket and strengthened my determination to deliver the letter. However, after entering Beigou Village, I encountered many dangers, first being blocked by a group of strange insects, and then being forced into a narrow path by villagers, which led to a cliff, with constant thrills. When I left Beigou Village, the stone in my hand was discovered to be an egg, which belonged to a ferocious animal called Renmao. After returning to the county town, strange things happened again, and my colleague was bitten by Renmao because of the egg. At this time, a mysterious person appeared. He told me that everything I had experienced was related to a person named Mao Kuizi. To save my colleague, I and Lao Cong's granddaughter, Yin Yue, returned to Beigou Village, where the egg hatched into a pet that protected me. The appearance of Jinnan and the revelation of Jinnan and Yin Yue's backgrounds made me feel more and more that I had fallen into a pre-set trap since delivering this letter...