La muchacha de los libros usados tells the story of a girl whose family sold her to a soldier. Her life then unravels as a series of experiences related to the organized, symmetrical life of the army. Still almost a child, the girl is forced by the soldier to live in the barracks, treating her like a prized object. The night he decides to engage in sexual intercourse with her, the girl runs away and is hit by a bus. While struggling between life and death, the girl looks back over events in her life, realizing the symmetries at play in most people's lives, as well as the levels of control and repression enacted by people. The moment she supposedly recovers, she decides to leave her husband/buyer for good.