Book 2 Chapter 18 "THE EARTH KING"

The group breaks into the Earth King's palace to warn Earth King Kuei about the war. They eventually convince the King by showing him the destroyed Fire Nation drill, resulting in Long Feng seemingly being arrested for treason. Meanwhile, Zuko fights an illness which Iroh believes is a manifestation of the deep internal conflict within himself after setting Appa free. Team Avatar is presented with information that was intercepted by Long Feng: Toph receives a letter from her mother saying she is in Ba Sing Se and wants to see her. Sokka and Katara are given an intelligence report that confirms the location of their father Hakoda, while Aang receives the letter from Guru Pathik, offering to help him master the Avatar State. The team decides to temporarily part ways to accomplish all their goals. Unbeknownst to them as they leave, Azula, Mai and Ty Lee slip into Ba Sing Se impersonating the Kyoshi Warriors. The letter from Toph's mother is revealed to be a setup for her capture by Xin Fu and Master Yu, while Long Feng is shown to still be in command of the Dai Li while in prison.