After Qin Shihuang unified the six kingdoms, he secretly sent troops to search for the elixir of immortality around the world. During the Republic of China, a Qin-Han Tongdian recorded this story in detail. This team that could cross mountains and go to Southeast Asia was mysteriously named the "Immortal Underworld Army". After just ten years of searching for the elixir of immortality, the entire army was transformed overnight. Many years later, a new force suddenly emerged in the ancient town in the south of the Yangtze River. As a descendant of the four major families, it seems that there is some shocking secret hidden in the dark. A bloody conspiracy gradually surfaced. What action will Lu Xin, a descendant of the four major families, take?