"The Old Gringo" is a novel by Carlos Fuentes that tells the story of an American writer named Ambrose Bierce who travels to Mexico during the Mexican Revolution. He seeks adventure and a sense of purpose, but his journey leads him into a world of conflict and danger. The narrative intertwines the lives of Bierce, a young Mexican woman named Laura, and a revolutionary leader, General Arroyo. Through their experiences, the novel explores themes of identity, power, and the impact of war on individuals and society. The story reflects the complexities of cultural and historical relationships between Mexico and the United States.