Sozin's Comet, Part 1: The Phoenix King

This the 1st part of the upcoming 4-part finale of Avatar. These last four episodes will be combined together to create a 2-hour long movie. The kids return to the Fire Nation and prepare for their final confrontation with Firelord Ozai, but they discover that the Firelord has plans of his own: he has ordained himself Phoenix Lord and appointed Princess Azula as the next Firelord. In the spectacular 4-part finale of Avatar Book 3: Fire, Aang fulfills his destiny as Avatar and confronts the Firelord in the greatest battle of the series.

Fan Theories Derived from NYCC Trailer

 * Katara will Bloodbend again.
 * Katara will fight in the Fire Nation Royal Palace.
 * Azula will be confronted by either her mother, Ursa, or an image of her and Azula will lose her temper.
 * The Comet might come before Ozai is defeated.
 * June the Bounty Hunter will return.
 * Katara may hug Zuko.

Fan Theories based on Series Continuity

 * Either Aang and Ozai might both tap into the power of Sozin's Comet or Aang might use the Avatar State and Ozai might use the Comet.
 * Iroh might return and more information on the Order of the White Lotus might be revealed.
 * Zuko may create lightning.
 * Jeong Jeong is still an unfinished chapter so something might be revealed and he may return.
 * King Bumi might find "the right time to strike" and also return.
 * Sokka's messenger hawk, Hawky, may finally return.
 * Toph's parents may finally accept Toph.
 * Koh may return.
 * Ty Lee and Mai may return.
 * Zuko and Katara might rescue the Invasion Force, The Kyoshi Warriors and maybe even Mai and Ty Lee from the prison Iroh previously stayed at.
 * Ursa may have a touching reunion with Zuko.
 * Iroh, Piandao, and Jeong Jeong might all be part of the Order of the White Lotus