Avatar: The Last Airbender Season 3 Episode 20 : Sozin's Comet: Into the Inferno (3)
Azula's mental stability, undermined by the betrayal of her friends at the Boiling Rock, begins to deteriorate as her coronation as Firelord approaches. Zuko and Katara confront her right when she is about to be crowned Firelord, but Azula challenges her brother to an Agni Kai. Zuko, although initially winning, is gravely injured when Azula throws lighting at Katara and he dives in the way. Aang duels Ozai without result, still unwilling to kill him. Sokka, Toph, and Suki attempt to halt the Airship fleet but are soon separated, while the Order of the White Lotus battles for Ba Sing Se's freedom.