In 1979, mysterious skeletons of creatures were found in Kunlun Mountain. The expedition team led by Hu Bayi (played by Mark Chao) went deep into the hinterland of Kunlun Mountain to find more secrets about the remains of ancient creatures. However, they were attacked by different mysterious creatures in the process and accidentally fell into the Nine-story Demon Tower. Except for Hu Bayi, the life and death of the group became a mystery. After retiring from the army, Hu Bayi returned to Beijing and reunited with his childhood friend Wang Kaixuan (played by Feng Li). He embarked on a journey to explore unknown civilizations again in the gap between the mysterious man (played by Li Chen) and the scientific expedition team (played by Feng Shaofeng, Tang Yan, and Li Guangjie). On the way, he met Shirley Yang (played by Yao Chen), and the familiar face awakened his memory of the days when he was in the expedition team. This trip is dangerous. Before they can figure out Shirley's true identity, Hu Bayi, Shirley, Wang Pangzi and their group are bombed by unknown creatures in Prince's Tomb and Oil Town. Everything that happens here points to the Nine-Story Demon Tower again, and what awaits them this time is a thousand-year-old unsolved mystery...