Sacred Land Defiled!

Avatar Aang asks his friends to help him honor Yangchen's Festival—one of the highest Air Nomad holidays, which hasn't been celebrated in over one hundred years. But cryptic visits from the spirit of Avatar Yangchen herself lead Aang to discover a jointly owned Fire Nation and Earth Kingdom refinery—operating on land sacred to the Airbenders! Is this simply a case of corporate greed or is something more mysterious happening?