This novel is about the disappearance of American writer Ambrose Bierce, who went missing in 1913 while visiting Mexico. Fuentes suggests that Bierce first went to Mexico in order to see a general in the Civil War, called Pancho Villa. After crossing the Mexican border, Bierce went missing, so Fuentes imagines what might have happened to him afterward. Although Bierce is the protagonist, we might also argue that this novel is about Harriet Winslow and her memories.
In the frame narrative of the novel, Harriet Winslow remembers her time in Mexico, after she decided to work there as an English teacher. There, she sees the destruction caused by the Civil War and meets the old gringo (Bierce) and Arroyo. They go their separate ways and later meet again, where the old gringo and Harriet confess their love for each other. Arroyo becomes jealous and forces Harriet to have sex with him under threat. When the old gringo finds out about this he burns Arroyo's prized possession (a deed proving he is heir to a house,) and Arroyo kills him in return. Later in the novel, it is revealed that the old gringo is actually Ambrose Bierce, and this is a speculative account of what happened to him when he went missing.