On the eighth day of the twelfth lunar month, Yong'an City in Daliang was closed due to wind and snow, but the oil lamps in the "Jishitang" in the west of the city were lit until late at night. Shen Li, the orphan of the former princess and the successor of the Medical Saint, is dormant here as an ordinary doctor. Hidden in the secret pocket of her sleeve is the "Hidden Phoenix Order" that carries the mission of restoring the country. There is also a cold poison related to the massacre of the family ten years ago lurking in her body.
In the cold night, a woman brought a child whose heart was attacked by cold poison to seek medical treatment. When Shen Li applied acupuncture to save the child, the cold poison in his body unexpectedly started to change, which brought back the painful memory of the night when the family was exterminated. Her mother passed down her legacy with a blood sacrifice and asked her to find the "mysterious map". Before he could recover, Xiao Yan, who was wearing a black brocade robe and had an extraordinary bearing, came to the door with the "Yu Lin Ling" and asked her to diagnose and treat the "heart disease caused by the full moon" for the old lady in the mansion.
Shen Li notices something strange about Xiao Yan's cuffs, the Shadow Guard Pavilion, and his heart ailment, but still decides to go to the appointment - this is not only an opportunity to get close to the core of the court and explore the truth about the cold poison and the longevity pill, but also allows her and Xiao Yan, who carries family secrets and hidden ambitions of subversion, to lay the foundation for the entanglement of fate in the snowy night.
