From the introduction:
France, 1870. A terrible, incurable disease is ravaging the population, leaving its victims twitching and writhing in agony, waiting for a merciful death to claim them. Two factions have arisen to combat this dreaded plague, each with their own beliefs about its nature, each with their own methods of tackling it. Who shall be the one to save all of France from its dread effects? Who, in the end, is right? That is something for you to decide.