An Indian boy who tends llamas in a hidden valley in Peru learns the traditions and secrets of his Inca ancestors.

Born in Las Vegas, New Mexico, Ann Nolan Clark graduated from New Mexico Highlands University in 1919 with a degree in education. For many years she worked for the US Bureau of Indian Affairs as a teacher of Native American students. After noticing that her Tesuque Pueblo school had scarcely any educational material geared toward Native Americans, she began to write children's books that catered to the language and culture of her students. While traveling through Mexico, Guatemala, Peru, Ecuador, Costa Rica, and Brazil under the employment of the Institute of Inter-American Affairs, Clark was inspired to write her 1953 Newbery Medal–winning book Secret of the Andes.