Zhang Chen often dreams of an ancient woman, but at the end of his dreams he is always frightened when awakened by her fierce face. Later, he sees the place in his dreams on the Internet, so he plans to go there with his friend Wuxia to find out. On the way, they meet Lan Xi and Li Zhi who are looking for inspiration to write a horror script, so the four of them walk together. After arriving at that place, supernatural events continued to occur. With the help of Xiaoxian (the woman in Zhang Chen's dream), the four of them slowly got closer to the truth controlled by the old demon.

The movie is based on a real historic event. During French's invading war against China in 1885, the French army took over Zhengnan Guan located in the Guangxi Province. Wishing to protect their beloved country, the 70 years old General Feng Zicai and his two sons volunteered to join the battle. The general understood it would be a difficult battle to win as the French soldiers held much more advanced equipment, resources and weapons. To show his devotion and determination, he brought his own coffin alongside with him to the war zone. He also utilized his experience with the Zhangnan Guan terrain to pave out strategies, made weapons applicable to their situations. These actions bolstered the morale tremendously, and prepared them well for the war. As a result, although the Chinese soldiers sustained heavy losses, they turned the tide of the battle and won.