The film is set against the backdrop of the mythology of the Classic of Mountains and Seas . It tells the story of Peng Lai, a junior high school girl, who accidentally enters a mysterious cave that seals ancient books during her summer vacation trip and releases four ferocious beasts: Qiongqi , Hundun (Dijiang), Taotie , and Taowu . In order to restore world order, she uses the power of the mountain and sea beasts she has subdued to fight against the ferocious beasts. In the end, she successfully repairs the book and achieves self-growth.