Naomi, Owen, and Gram are appealing characters. Naomi worries, keeps lists of things that interest her, and hangs out in the school library with other social outcasts and the eccentric librarian. Owen is relentlessly optimistic and cheerful, and his rather lopsided appearance masks intelligence and a good heart. Gram works hard and believes in the power of positive thinking, and she has managed to make their meager existence seem rich and cozy.
The only character who doesn't ring true is the children's mother, Skyla, who seems to have no redeeming qualities at all. She is maliciously selfish, scheming, devious, alcoholic, abusive, and just plain mean, and shows not the slightest sign of affection for anyone, much less her children or her grandmother. While this certainly enhances the reader's sympathy for already sympathetic characters, it does make Skyla a rather cardboard villain, and lessens the complexity of the situation. But the author makes up for this with the richness of the scenes in Mexico, which spring to vivid life after the pale California scenes. They seem to be shot through a warmer filter, and will make readers long for a trip to Mexico.