Avignon, the Papal City, heart of Christendom, January 1348. Guy de Chauliac, surgeon to Pope Clement VI, witnesses the arrival of a mysterious sickness spreading from the ports of Marseille. Within weeks, the disease ravages Avignon, sweeps across France, then the whole of Europe, cutting down nearly half the population.
As physicians and cardinals flee, Chauliac stays. He forms a clandestine alliance with Nathan Bonjuste, a Jewish doctor, in an attempt to understand the causes of the disease, find remedies, and contain the epidemic. Should the population be quarantined? As Chauliac himself falls ill, hovering between life and death, society begins to fracture. Conspiracy theories, pogroms against Jews accused of poisoning the wells, panic and famine — Pope Clement VI, leader of a world in collapse, struggles to hold back the chaos.