Su Tang, a doctor from the Department of Modern Medicine, traveled through his soul into the body of a foolish palace maid who was about to be burned to death in the Daqian Dynasty. She discovered that a vicious epidemic was breaking out in the palace she was traveling through (it was initially misdiagnosed as smallpox, but was actually a man-made insect plague). However, what is even more frightening is that a dangerous "blood poison" was planted in the original owner's body, making her the "living petri dish" and "source of infection" of this plague. She was made a scapegoat by those in power. Relying on modern medicine's profound understanding of microbiology and epidemic prevention, as well as his practical experience as Médecins Sans Frontières in his previous life, Su Tang survived in the cracks as a "madman" and "witch" while secretly investigating the source of this man-made plague. She discovered that the disease was not a natural disaster, but an "artificial plague" created by a powerful imperial concubine in the harem, together with imperial doctors and frontier merchants, using wizards to spread poison. The purpose was to completely disrupt the government and eliminate the prince and opposition forces before the smallpox vaccine was available. In the countdown to death when the blood poison bites back, Su Tang wants to use his mortal body to break a biochemical crisis woven by the powerful.
