The Crystal City

The Crystal City is an alternate history and fantasy novel by the American writer Orson Scott Card, published in 2003. It is the sixth book in The Tales of Alvin Maker, and its central figure is Alvin Miller, a seventh son of a seventh son whose knack gives him power over the world he lives in.

Alvin and Arthur stay at a boarding house where mixed-blood children are looked after by Papa Moose and Mama Squirrel, and there Alvin cleans the mosquitoes and the disease out of a well. A young woman the people call Dead Mary sees what he has done and asks him to come and heal her mother, who has yellow fever, and he agrees to do it.

The healing radiates outward through the city and takes the fever with it, and in doing so it averts a war that the United States and Nueva Barcelona were about to fight over slavery. Alvin is then approached by an African woman named La Tia, who wants his help in getting the enslaved and the displaced French out of the city, and the book builds towards a crossing that can only be made by magic.