Sozin's Comet: The Final Battle
The Comet appears in the sky, and Azula's coronation takes place. Azula banishes nearly all of her subjects (including her Dai Li agents) in fear of betrayal. Her paranoia and loneliness begin to drive her insane. Before she is crowned, Zuko and Katara arrive. Zuko accepts Azula's challenge of an Agni Kai, because he feels that something is wrong with Azula and he does not want Katara injured. Just as Zuko is on the verge of defeating Azula, she shoots a bolt of lightning at Katara instead of Zuko. Zuko intercepts the lightning, preventing Katara from getting hurt, but injures himself after he fails to correctly redirect the lightning.