Her novel, “Eating Ashes,” opens with the unnamed narrator already in the throes of grief, but the plot begins more than a decade earlier. After her mother leaves Mexico City for Spain in search of work and freedom, the narrator becomes the primary caretaker of her younger brother, Diego, a sensitive boy who waves at airplanes in hopes that their mother might be coming back. But when the siblings finally make it to Madrid, the narrator discovers that Spain isn’t the paradise her mother had promised: “In Mexico you could say we were poor. … In Madrid, though, people still looked at us like we were poor, but also like we were scum.”