Ellis Whitman is a fourteen-year-old boy off to school in the east. His mentor is Goat Man - a dope smoker who lives in the pool house at the back of his mother's house in Tucson, Arizona, growing his own hybrid weed and tending three goats. His mother, Wendy, is divorced from Frank, who has now gone off with another woman.
Ellis's school career promises to get off to a good start with Goat Man supplying him top-quality weed to keep him going. Together they embark on a trip to Mexico to trek the goats back to Arizona, but things get complicated when one of the goats plunges into a flooded river and Goat Man too, trying to save his goat, gets swept away . . .