Wren Baker is an anxious twelve-year-old, so when her mother goes into a hospital for depression, and she and her younger brother, who has Asperger's syndrome, go to live with her aunt and her cousin, Silver, who have just recently moved to Pennsylvania, her stress level soars--especially since Silver is a fearless child who conceives a plan to climb Creeper Mountain and interview "Witch Weatherly" for the class history project.