The year is around 1300 AD and weak magic exists, as in demigods, magical auras, potions and alchemy, but not hardcore wizard magic. The city you live in has become ridden with plague and hundreds die every day. No one is certain, but most believe the vermin that populate the streets were the origin of the disease. The alchemists and doctors have tried everything, but no one can seem to stop its spread. What do you do? How would you cure the city, stop the plague’s spread, or would you simply pack up and hope you can outrun it?
Edit: Oh, think the Rat Plague in Dishonored, maybe I was subconsciously thinking about that when I wrote this.