The crazy old lady known only as La Curandera tells a tale that begins 500 years ago in the Aztec Empire at the peak of its strength and ends in her dirty little Arizona gift shop with four kids and a wayward Chupacabra, all of whom are meant to save the world from an ancient evil. Alas, it's a school night. But our heroes defy their destinies at tremendous cost when a new and yet very familiar foe is revealed.