This is a story about "using medicine as a spy and using drugs to control power", an ancient style of female channel conspiracy. The heroine is not the heir of a family of medical women, but the descendant of the last priest of the "spiritual doctor clan" that perished five hundred years ago. She used her identity as a doctor to weave an invisible espionage network between the backyard, the market, and the frontier. However, her people were regarded as a thorn in the side of royal families of all generations because of the "Nüshu", a lost spell that can control human nerves. She was secretly hunted by the royal family, but she had to cooperate with a "land prince" (the powerful prince who controlled the household registration and granary of the country) who wanted to overthrow the dynasty, and exchanged poison and intelligence for living space.
