The story tells that Cui, the hero, accidentally entered the underworld and became a teacher of Yin and Yang. His work experience in the underworld, what he saw and heard, and his struggle and cooperation with various ghosts constitute the main line of the whole novel.
In the novel, Cui gradually adapted to the life of the underworld through his own efforts and wisdom, and began his own path of practice. He made a lot of friends, including some mysterious beings, such as impermanence, impermanence, cow's head and horse's face, etc. He also encountered many dangers and challenges, including fighting evil spirits and solving supernatural phenomena.
The whole novel is full of humor and suspense, and also discusses some profound philosophical issues, such as life and death, reincarnation, human nature and so on. It is not only an interesting fantasy novel, but also a literary work of thinking about life.