In 1917, in Liujiacun, a village in the southwestern border of China. Liu Jinxie (played by Donnie Yen) and his wife Ayu (played by Tang Wei) raise their two sons, Fangzheng and Xiaotian, leading a simple and happy life. Until one day, two uninvited guests disrupt the tranquility of Liujiacun and destroy the life of the Jinxie family. These two attempted to rob the village's treasury and were unexpectedly confronted by Jinxie, leading to a chaotic fight where one of the robbers is unintentionally killed by him. As one of the robbers is a wanted criminal by the government, the county magistrate is overjoyed, and the villagers regard Jinxie as a great hero. However, this seemingly ordinary accidental killing arouses suspicion in one person, Xu Baijiu (played by Takeshi Kaneshiro), a constable from the county office. Analyzing the clues, Xu deduces that the robbers were killed by someone with exceptional martial arts skills, prompting him to linger in the village to observe, investigate, and test Jinxie repeatedly. Throughout this process, Jinxie's mysterious true identity gradually comes to light, while Liujiacun faces an unprecedented crisis...