Trapped in a world where the legends of Tewa mythology walk free, a young girl must solve an ancient mystery in order to return to her own world. It is the beginning of summer, and twelve-year-old Maggie is angry about her family's move from San Diego to Albuquerque, New Mexico. Lonely and resentful at her new circumstances, Maggie and her dog Jack explore their new neighborhood and soon find the shady trail leading up to the Rio Grande.

While playing by the river, Jack startles a strange young boy, Ash. Maggie is slowly drawn away from the real world of her family and into Ash's land, one populated by myths and legends. Threatening all is Shriveled Corn Man, a powerful sorcerer in search of vengeance for wrongs long past. Guided by the trickster Coyote and the cryptic Spider Old Woman, Maggie and Jack must travel across Ash's world in order to free their new friend and his people.