Qingwu Ancient Village, located deep in the mountains, is shrouded in the lingering blue mist all year round. There are three dead rules spread in the village: you must stay indoors on the fifteenth day of every month, avoid wearing red clothes, and never pick up things dropped in the fog. The village guard Chen Jiugen has guarded the ancient village for generations and made a living by punching paper figures to "suppress fog". However, on the eve of a certain National Day, he discovered that the eyes of the paper figures he had punched with his own hands were bleeding. At the same time, Chen Nian'an, who was studying abroad, received the news that his grandfather had drowned. When he rushed back to the village, he saw his grandfather's body wearing a red shroud and died in the old well that had dried up - this completely violated the rules of the ancient village. Two clues run parallel. Chen Jiugen faces the intrusion of the "fog spirit" in the village, while Chen Nian'an goes out to trace the folklore archives related to the ancient village. The two gradually discover that the death of his grandfather and the abnormalities of the paper man are related to a deliberately forgotten "fog god sacrifice" in the ancient village a hundred years ago. Deep in the blue mist, there seems to be a more terrifying existence.
