The story takes place in the world of immortality where mirrors are embedded and poisonous miasma is everywhere. The protagonist, Yu Anlei, was originally a modern emergency doctor, but accidentally traveled through time and became a low-level disciple of the Baimias Sect with mediocre qualifications, specializing in drug testing. In a desperate situation where she was almost killed by a poisonous backlash, she relied on modern toxicology knowledge to analyze and reconstruct the deadly toxins, creating "targeted and controllable poisons", and unexpectedly touched the strange talent hidden in her body that resonated with the mirror world. Based on the concept of "physicians detoxify and poison masters use poisons, the essence of which is to control the state of life", she embarks on a unique path of "double cultivation of medicine and poison". While exploring the sect's forbidden area "Remnable Mirror Abyss", she met "Xuan Ying", a demon boy who was ostracized due to different ideas, and got involved in the factional struggle within the Bai Mi Sect over the authenticity of the "Ancient Poison Sutra".
