Avatar Last Airbender TP Vol 07 Rift Part 1

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 the cause of the pollution Aang finds there, or is a more mysterious menace afoot?