Avatar Aang asks his friends to help him honor Yangchen's Festival - an extremely sacred Air Nomad holiday that has not been held in over a hundred years. However, 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 something more mysterious happening?

In the Fire Nation, Uncle Iroh still awaits the return of Fire Lord Zuko, who is bringing home his long lost mother, Ursa, as well as her new family - for the first time since her banishment. owever, the capital city faces a new uproar caused by the New Ozai Society, who aim to dethrone Zuko in favor of his imprisoned father, forcing Zuko to protect his family against the legacy of Ozai. Besides the political turmoil, personal drama erupts - as the Fire Lord also needs to face his ex-girlfriend, Mai.

The Search primarily focused on the mystery surrounding Zuko and Azula's long-lost mother, (Avatar Roku's granddaughter) Ursa. It will also reveal the details of former Princess Azula's imprisonment in a Fire Nation mental institution and what effects the imprisonment has had on her. The main characters will be the Fire Nation family, particularly Zuko and Azula. Avatar Aang, Toph, Sokka, and Katara will also appear, but in a more limited role than they have had in previous novels, as recurring characters. Gene Yang has noted that the series will focus more on the supernatural side of the Avatar world.

Ever since the conclusion of Avatar: The Last Airbender, its millions of fans have been hungry for more - and it''s finally here! Think of this as the Book Four (season 4) of Avatar because it continues Aang's story from right where the TV series left off. This series rejoins Aang and friends for exciting new adventures, beginning with a face-off against the Fire Nation that threatens to throw the world into another war, testing all of Aang's powers and ingenuity.