The Old Gringo tells the story of Ambrose Bierce, the American author, soldier, and journalist, and of his last mysterious days in Mexico living among Pancho Villa's soldiers - particularly his encounter with one of Villa's generals, Tomas Arroyo, as well as with a spirited young American woman named Harriet Winslow. In the end, the incompatibility between Mexico and the United States (or paradoxically, their intimacy) claims both Bierce and Arroyo, in a novel that is, most of all, about the tragic history of these two cultures in conflict.