Add a new rule, “Other Rituals”:
A Villager at the church carrying Remedies of one each of Salt, Well Water, and Nightshade may remove all of them to perform a Saltwater Ritual by making a blog post indicating this. When a Villager performs a Saltwater Ritual, they gain the symptom Death, and all Villagers without the symptom Death are cured of the Black Death.
An old account of a previous Black Death outbreak and subsequent cure is discovered in the disheveled Zahndorf library by one of the few surviving literate villagers. Over two centuries ago, they chose a citizen to perform the Saltwater Ritual by drawing straws, but now we live in more civilized times.