Garza Twins, Book 1: The Smoking Mirror

Carol and Johnny Garza are 12-year-old twins whose lives in a small Texas town are forever changed by their mother's unexplained disappearance. Shipped off to relatives in Mexico by their grieving father, the twins soon learn that their mother is a nagual, a shapeshifter, and that they have inherited her powers. In order to rescue her, they will have to descend into the Aztec underworld and face the dangers that await them. Winner Pura Belpré Author Honor Award.