Cities of the Plain is the third and final book in the Border Trilogy.

In Cities of the Plain, two men marked by the boyhood adventures of All the Pretty Horses and The Crossing now stand together, between their vivid pasts and uncertain futures, to confront a country changing beyond recognition. In the fall of 1952, John Grady Cole and Billy Parham are cowboys on a New Mexico ranch encroached upon from the north by the military. On the southern horizon are the mountains of Mexico, where one of the men is drawn again and again, in this story of friendships and passion, to a love as dangerous as it is inevitable