Azula, the daughter of the Fire Lord Fire Lord Osei, clearly hates her brother Zuko, plotting to frame him throughout and sending a letter to General Zhao asking for an update on the mission.

Then An and his party came to Omashu City, a fortified Earth Kingdom city built on a mountain. The people were artists, scientists, and construction workers.Ann, Katara, and Sokka are smuggled into the city by a handsome man named Jay, who is actually the leader of a group of freedom fighters stationed in the forest.Katara took an immediate liking to him.

The city of Omashu is regularly bombarded by what are believed to be the Fire Nation, so Ann decides to stay and help mechanic Sai and his son Sean uncover the truth behind the conspiracy.But when Katara discovered that Sai was meeting with a Fire Nation spy, Jay suddenly showed up and told her that Sai was a Fire Nation spy who had been selling secrets and designs to the Fire Nation.She follows Jay as he tracks down Fire Nation spies and fights his companions.Jay is the leader of a group of freedom fighters.His companions included a duke and a little boy.Jay helps Katara further develop her water powers by remembering her mother.

Ann and Sean investigate a cave and discover that Jay is the bomb maker.The team is split, with Katara trusting Jay and Sokka not buying into the idea that Sai is a traitor.In the end, it turns out that the bomb maker is Jie, and Jie will sacrifice a lot of innocent lives in order to find the spy.Jay reveals that he planted a bomb on Sai, intending to blow it up when he meets the king of Omashu City.The team tries to stop Sai, but encounters Ai and Zuko.

Aang fights Zuko and asks him why he wanted to capture him.Katara and Sokka manage to catch up to Sai and stop the explosion.Princess Azula secretly sends a letter to General Zhao, asking him to provide the latest information on her brother Zuko's mission.In the finale, chaos erupted when Zuko used his fire powers too freely, attracting the attention of the Earth Kingdom military, who arrested Aang and Zuko, with Zuko able to escape with love and help.