Avatar: The Last Airbender Season 2 Episode 3 : Return to Omashu
Omashu has been captured by the Fire Nation. Aang and friends sneak in and are nearly captured, but Sokka fakes a deadly illness to scare off the guards. They meet a resistance movement, and help the whole city escape with the same fake epidemic. The Fire Nation Governor's son accidentally leaves with the citizens. Aang attempts to trade him for King Bumi, but Princess Azula calls off the trade. Aang manages to rescue Bumi after a fight with Azula, but Bumi allows himself to be recaptured, saying that he must wait for a more proper time. He instructs Aang to find an Earthbending teacher who "waits and listens".