In southwest China, isolated from the world and surrounded by mountains, there is a village where everyone lives a long life and has its own rules. The emperor of the Qing Dynasty named it "Changshou Town". One day, an infectious disease broke out, and the local official sent a doctor (played by Simon Yam) to treat it. He found Niu Jieshi (played by Huang Bo) dying outside the town. After entering the village, the villagers who used to be kind and gentle turned against their usual behavior. Not only did they refuse to help Niu Jieshi and avoid him as if he were a plague, they also took out their anger on the doctor for meddling in their affairs. The old mayor (played by Ma Jingwu) personally brought the doctor (played by Alec Su), the midwife (played by Liang Jing), the painter, the old patriarch and others to do everything they could to prevent the doctor from rescuing Niu Jieshi. Niu Jieshi was ultimately not saved, and the doctor could not find the reason for his sudden death. The doctor was frustrated by the townspeople's unwelcome and uncooperative attitude towards him. Just as he was about to leave, he accidentally discovered a secret hidden on the cliff by the entire town. With many doubts, the doctor decided to visit Changshou Town secretly. Until he met a boy by chance, the truth of the Changshou Town mystery was gradually revealed... The film is adapted from Chen Tiejun's novella "Child's Play Murder".