David and his wife, Jennifer, teach underprivileged communities in Texas that are often Spanish-speaking. To learn the language of their students, they decide to spend a few months at a college in Mexico, heralded by warnings from their friend Tony about danger and dogs. David heeds these warnings little and is astonished when a potbellied dog attacks him, tearing at his backpack. He and Jennifer find another dog dead outside of their house, gruesomely mauled. When they see a stone pot in the shape of a potbellied dog, they decide to buy it for Tony, hoping they'll be able to laugh off the bizarre incidents of the past few days.

But the pot is only the beginning. David asks his Spanish teacher about the history of the dogs, and he learns that they once fed on human flesh, and the Chichimec ate the dogs in return, in a life-and-death cycle of cannibalism. His teacher insists he leave the pot in Mexico when he returns home. David laughs off this warning and brings it along, only for he and Jennifer's bus back to the border to go off a cliff. Jennifer's leg is broken in the crash, and the potbellied dogs attack her viciously as she struggles with the injury.

David thinks they'll be safe when they are no longer in Mexico, but the dogs continue to haunt them. He breaks the pot and disposes of it, hoping this action will help, but they follow David and Jennifer anyways - all the way to Jennifer's parent's house, where she disappears.

When they find her body twelve days later, David already knows what happened to her. Jennifer's family has the blood of the Chichimec in their veins. The problem was never the pot; Jennifer was destined for death, and the dogs merely helped her along.