Fifty years after World War III, the residents of New Orleans struggle daily just to survive. Despite being surrounded by the waters of the Mississippi, latent radiation and pollution have made clean drinking water hard to come by. So Rue has reason to worry when their water purifier breaks down and her husband’s depression keeps him from fixing it. She reluctantly accepts the aid of her neighbor’s son Joseph, who had taken to practicing the dark arts at the Circle of Magi.

But as her husband’s increased hostility makes her more dependent on Joseph just to survive, Rue has to make a decision that will impact not just her own life, but the lives of everyone in Bywater.