An old man comes to seek the help of Mr. Wu and his two companions with a mysterious incident that occurred in the southwestern mountainous area. Fog rises in the mountains and villagers disappear. Everyone pursues the mystery to the abandoned black gold mine in the mountainous area, discovering that all the strangeness comes from mysterious creatures deep in the mine. After experiencing multiple crises, the three not only unravel the old man's conspiracy, but also successfully solve the problem of heavy fog....

A mysterious letter sent to Wu Xie's late grandfather Wu Laogou disrupts the retirement plans of Wu Xie, Zhang Qiling, and Wang Pangzi. The letter points to a "Comet" tomb in Outer Mongolia and the invincible trio decides to explore it, but unexpectedly gets involved in an unimaginable adventure. With the sinister Mongolian bandits, the countdown to escape from the "Comet" tomb, the unnerving rules of the tomb chamber, and the invisible "it”... The invincible trio has to give it a shot......