There are laws in the three realms, with yin and yang on each side. Lin Danqiu lives in the secular world, enforcing the laws of yin and yang. On one side is the human warmth and warmth of the human world, and on the other side is the fate of life and death in the three realms of the underworld. She takes her spirit companion with her, walks through the fog, solves mysterious cases, travels back and forth between good and evil, uncovers false obsessions, extradits thousands of souls, and writes a detective legend that spans Yin and Yang.
