Josefina and her sisters distrust learning to read and write, as well as other changes their Tía Dolores is bringing to the household, because they fear they will lose their memories of their mother.

Josefina hopes to become a "curandera" or healer like Tía Magdalena, and she is tested just before her tenth birthday when a friend receives a potentially fatal snakebite.

When Tía Dolores, the beloved aunt who has cared for the Montoya family since the death of their mother, announces that she is planning to leave, Josefina and her sisters try to find a way to change her mind.