Harriet Winslow, a spinster schoolteacher from New England, arrives in Mexico to teach English to the children of a wealthy landowner. However, she is kidnapped by General Tomas Arroyo, the leader of a revolutionary group fighting against the corrupt Mexican government. Meanwhile, Ambrose "Old Gringo" Bierce, an elderly and disillusioned American journalist and writer, has also arrived in Mexico. He is secretly searching for a place to die, having lived a full life and become disillusioned with politics and society in the United States.
Old Gringo becomes a close friend of General Arroyo and begins to have a romantic interest in Winslow. However, Bierce deliberately provokes the general in order to force him to kill him, as he feels that this is a more dignified and honorable death than succumbing to illness. Winslow becomes determined to fulfill Bierce's wishes, and she helps him find the right place to die.
As Winslow spends more time with Arroyo, she becomes increasingly sympathetic to his cause, and the two begin a passionate affair. However, when Arroyo discovers that Winslow is helping Bierce die, he becomes angry and jealous, and their relationship is strained. Eventually, Bierce dies peacefully, and Winslow returns to the United States.
The film explores themes of friendship, passion, and the search for meaning and dignity in life. It is based on the novel of the same name by Carlos Fuentes, which was inspired by the real-life disappearance of Ambrose Bierce during the Mexican Revolution.