Avatar: The Last Airbender: Season 3, Episode 18
Sozin's Comet: Part 1 - The Phoenix King (19 Jul. 2008)
Sozin's Comet is only three days away. Zuko tells the others what the Fire Lord plans on the day of the comet and the gang realizes that they must stop him before then. But Aang doubts that he can do what is expected of him.