After returning to Hangzhou from his past two adventures in Nansha, Wu Xie suddenly receives a call from his long-lost childhood friend Lao Yang. He talks to Wu Xie about their adventure in the hinterlands of Qinling Mountain three years ago and invites Wu Xie to explore the ancient ruins there again. During their adventure, Wu Xie and Lao Yang witness a giant taimen, a grand underground waterfall, and an unfathomable ancient sacred tree. Meanwhile Zhang Qiling, who has been elusive from the start, is secretly helping Wu Xie.