Lydia Quixano Pérez lives in the Mexican city of Acapulco. She runs a bookstore. She has a son, Luca, the love of her life, and a wonderful husband who is a journalist. And while there are cracks beginning to show in Acapulco because of the drug cartels, her life is, by and large, fairly comfortable.

Even though she knows they'll never sell, Lydia stocks some of her all-time favorite books in her store. And then one day a man enters the shop to browse and comes up to the register with a few...