The book is based on the only four-character record of the alien beast "ki" in the "Book of Mountains and Seas" as the starting point, and fictionalizes a legend of struggling to survive in the cracks between the three worlds of gods, humans, and demons. This two-headed dog with two faces - the left one is as docile as a bulldog, and the right one is as ferocious as a ferocious beast - was born in the wild desert. It successively sought refuge with Kunlun, the Emperor of China and Jiuli Chiyou. However, due to its innate split nature, it chose betrayal and self-preservation at every critical moment. It survives through deception and seeks strength through biting, but it also tastes peace in its short stay in the countryside. The story finally returns to a desolate background: it returns to the sand cave where it was born and stops running under the moonlight. The author spent five years working hard to write a biography of this strange beast that was destined to be omitted from official history. He is not only questioning the fate of a two-headed dog, but also whether every life trying to survive the split can find a place where the two halves of the soul can calm down at the same time.
