Rattlesnake

TV-movie-quality throwaway flick about a woman whose daughter gets bit by a rattlesnake out in the desert, and is helped by a strange old woman in a nearby trailer which vanishes afterwards. Later, mysterious strangers tell her she must take a soul for the one that has been saved, otherwise the kid’s fatal injury will revert, and she must do it before sunset, because, movie, obviously. Eventually she kills someone and her kid is safe. Who was that old woman? What strange power is behind this ordeal? It doesn’t matter, and it’d better not, because we never find out.