 The Fire Nation is attacking the North Pole and Sokka, Katara, and Yue are looking for Aang. Zuko has Aang, but Aang is in the spirit world, where he meets Avatar Roku. Zuko and Aang are trapped in a cave during a storm, where Zuko shares some inner turmoil with Aang, who is in the Spirit World. At the water tribe, the firebenders are winning. Iroh attacks Zhao when Zhao reveals that he wants to kill the spirits of the moon and the ocean. In the Spirit World, Aang meets Koh the Face Stealer, who tells him that someone is planning on killing the spirits and he needs to stop them. Katara, Sokka, and Yue find Aang and they rescue him, taking Zuko with them. Zhao kills the moon spirit and the waterbenders lose their power. Yue reveals that the spirit once saved her. Iroh and Aang team up against Zhao. Zhao and Zuko escape as Aang turns into a giant spirit and goes to fight the firebenders. Elsewhere, Zuko and Zhao fight desperately. Yue sacrifices her own life to save the moon spirit. The moon returns and Aang turns back to himself. But the spirit still has one more mission. It kills Zhao. In the end, everything is well. Aang and the gang are heading to Ba Sing Sei, Zuko and Iroh have escaped, and in the Fire Nation, Azula is given a mission.