Zuko struggles to find shelter for himself and Aang in the frozen tundra, while Sokka, Katara and Yue search for them, as the Fire Nation forces assault the city. In the spirit world, Roku contacts Aang and tells him that the ocean and moon spirits crossed over to the mortal world long ago, and that only one spirit is old enough to remember: Koh the Face-Stealer. Aang must show no emotion or expression at all when meeting with him, lest his face be stolen off of his head. Aang finds out from Koh that the spirits’ names are Tui and La, “Push and pull”, and that they are in great danger. Aang finally figures out the Koi fish are the spirits, and quickly heads back to the physical world, indirectly leading Katara, Sokka, and Yue right to his body. Zuko is quickly defeated, but Aang chooses to save him. As they fly back, Admiral Zhao captures the moon spirit, causing the moon to turn red and the waterbenders to lose their bending. Aang and Iroh both warn Zhao, explaining that the entire world depends on the balance of the moon and ocean, including the Fire Nation. Zhao initially relents, but then attacks in a fit of rage, killing the spirit and darkening the moon completely. Iroh attacks Zhao and his guards, as Zhao quickly flees. Aang goes into the Avatar State and, joining with the ocean spirit, decimates the Fire Nation armada by forming a massive spiritual being. Zuko fights Zhao in retaliation for the assassination attempt, while Iroh remains with Team Avatar to try to revive the moon spirit. Iroh recognizes that Yue was touched by the moon spirit as a baby, by her snow white hair, and Yue gives back that spark of life, sacrificing herself to save the Moon Spirit. She assumes the form of the moon spirit, and gives Sokka a final kiss goodbye. Zhao is pulled underwater to his demise by the Ocean Spirit in retaliation for slaying the Moon Spirit, arrogantly refusing to accept Zuko’s help when he attempts to save him. The season ends with Pakku anointing Katara Aang’s new waterbending master as the group contemplates their next destination. Fire Lord Ozai assigns Zuko’s sister to hunt down her traitorous uncle and failure of a brother.