In a fictional world where every kind of medicine is banned, four very different people join forces. Shao Xia is a roaming swordsman, Wuming is a pharmacist with no memory of his past, Susu is a spirited constable, and Xu Changqing is a pharmacist in royal service. They band together while hunting a mysterious monster, and along the way they slowly uncover the dark truth hidden behind their city. Facing questions of trust and betrayal, and of power and what it costs, the group tries to save themselves and others in a world thrown out of balance.