The second half of the season finale begins with Sokka, Katara and Yue setting out on Appa. They are in search of Aang as the Fire Nation continues its attack on the Northern Water Tribe. As Zuko carries Aang across the polar ice cap, Aang’s spirit has arrived in what looks like a swamp. He then approaches a meditating monkey and asks for some assistance on finding the moon and ocean spirits. The annoyed monkey tells Aang to “Go… Away.” As Aang continues to ask the monkey for help, a glowing speck flies by and the monkey suggests Aang chase it, because it may be able to help him. Aang chased the glowing speck through the Spirit World, but when he finally manages to grasp it, the branch he was standing on disappears and Aang fell into the water. Roku’s image appeared as a reflection in the water and Roku’s voice greeted Aang. Back in the natural world, the polar ice cap begins to give way under Zuko and Aang’s weight. Zuko quickly runs while carrying Aang and manages to avoid falling through the ice. Just then, Zuko spoted a shelter in the distance, drags Aang’s body into the shelter and ties him up. Aang’s spirit tells Roku the Water Tribe is under attack and he needs help locating the Moon and Ocean spirits. Roku’s spirit ascends out of the water to face Aang as he tells Aang those spirits crossed over into the mortal world near the beginning and there is only one spirit old enough to help Aang.
The spirit is named Koh but Roku warns Aang to be careful as Koh is dangerous. Aang must not show any emotion when facing Koh or Koh will steal his face. Aang nods in understanding. Sokka, Katara and Yue, riding on Appa through the blizzard continue to look for Aang with no luck. Zuko talks to Aang’s body while Aang is in Spirit World. He laments how now that he has Aang, the blizzard prevents him from taking Aang back to the Fire Nation. Zuko then compares Aang’s natural talents to his own sister’s and recalls his struggles that have made him strong without any help from luck. Back at the Northern Water Tribe, Fire Nation troops move further into the city despite the waterbender warrior’s efforts. Iroh reminds Zhao that if the Water Tribe is not subdued by the rise of the full moon the waterbenders will be unbeatable. Zhao says he is planning to remove the moon as a factor. Iroh and Zhao are briefly interrupted as Han miserably fails at his attempt to attack Zhao and is thrown overboard. Zhao explained to Iroh how a long time ago he had stumbled upon the secret of the Moon Spirit’s mortal form in an underground library while serving as a young officer in the Earth Kingdom. Zhao then believed it was his destiny to kill the spirits. Iroh forcefully informs Zhao that the spirits are not to be trifled with. Zhao condescendingly tells Iroh he has heard of Iroh’s journey into the spirit world, but the Moon and Ocean gave up their immortality and will now pay the consequences. Aang approaches a large leafless tree, takes a deep breath and enters, calling out to Koh. Suddenly, Koh, with a large centipede like body and a face similar to a Japanese Noh mask, appears in front of Aang. As he switches faces, Koh explains to Aang that this is not their first encounter as one of Aang’s previous incarnations tried to kill Koh over the stealing of a loved one’s face. Aang takes a breath in to gather strength in order to not show any emotion as Koh tries to manipulate Aang into an opportunity to steal his face. At the same time, Aang’s body in the natural world also takes in a deep breath as Zuko looks on. Zuko comments that it looks like they will be in the shelter for awhile.Yue tries to comfort Katara by saying Zuko and Aang could not have gotten away. Katara says she’s not worried they got away, but that they didn’t. Sokka assures Katara that Zuko will not give up and both he and Aang are alive and they will find them.Menacingly, Koh asks, “So. How may I help you?” Aang tells Koh he needs to find the Moon and Ocean Spirits. Koh tells Aang the spirits’ names - Tui (push) and La (pull). Aang explains that and entire ure may be destroyed if he doesn’t get the spirits help. Koh informs Aang that it is the spirits who are in need his help as someone is planning on them. Aang asks how he can find the spirits to protect them. Koh tells Aang that he has already met them and their names are ebb and flow Tu and La. As Aang realizes the spirits’ mortal identities, he almost reveals his expression to Koh, narrowly avoiding the opportunity for Koh to steal his face. Upon leaving Koh’s tree, Aang tells Roku’s reflection that the spirits are in trouble and he needs to get back to the mortal world. Roku tells Aang Hae Bai is there to guide him back. Nightfall has come and the full moon has risen. The waterbending warriors exhibit massive power as they fiercely battle the Fire Nation soldiers. Zhao and his search party depart his ship in search of the Oasis. Zhao declares that when they get there “We’re going fishing”. Hae Bai takes Aang back to the gate and breaths out a light toward Aang which sends Aang’s spirit to the mortal world. However, to Aang’s dismay, he finds his body is not at the Oasis where it had been left. His spirit suddenly goes into a bright light form as it rushes to Aang’s body. Katara sees the light and realizes it’s Aang’s spirit and they turn Appa to follow the light as it reveals Zuko and Aang’s shelter. As his spirit rejoins his body, Aang suddenly sits up, forcefully acknowledges Zuko’s presence and then proceeds to blow a large gust of air which throws Zuko against the side of the shelter and him out of the shelter into the snow. Zuko manages to catch Aang, but then Appa approaches and Katara jumps down. Zuko says “Here for a rematch?” and Katara confidently replies “Trust me Zuko, it’s not going to be much of a match” as she forces Zuko about 40 feet into the air with a column of snow and then knocks him out by smashing him to the ground. Although he is in a hurry to save the spirits, Aang refuses to leave Zuko to die and they tie up the unconscious prince and take him with them. At the Oasis the location of the moon and ocean spirits, Zhao grabs the white fish and the sky goes red. The waterbending warriors lose their bending abilities. Yue says feels faint and Aang says he feels it too. Yue then explains how the Moon Spirit gave her life as a baby and how she received her name; Yue – for the Moon. Zhao begins arrogantly applauding his efforts to fulfill his destiny of the Moon Spirit. Momo then jumps onto Zhao’s head puling at Zhao’s hair and then flies over to Aang. Aang pleads with Zhao to consider how his actions will hurt everyone, not just the Water Tribe. Suddenly, Iroh appears confirming Aang’s words and tells Zhao if he harms the spirit, Iroh will unleash 10 fold the force against Zhao. Zhao releases the spirit back into the water, but then kills it with a fire blast - extinguishing moon. Iroh unleashes his firepower and easily defeats the soldiers accompanying Zhao, but Zhao manages to escape. The camera them pans behind Yue (still sitting on Appa) to reveal Zuko is missing. Iroh lifts the white fish out of the water and Yue says there’s no hope now, it’s over. Aang goes into the Avatar state and say powerfully “NO, It is NOT over.” He then walks into the Oasis and merges with the Ocean Spirit to head out and attack the Fire Nation invaders in the city. The Ocean Spirit (with Aang) then heads out to sea. As Zhao tries to escape, Zuko shoots a fireball at him. Shocked that Zuko is alive, Zhao confirms he tried to have Zuko killed because of Zuko’s Blue Spirit identity and for releasing the Avatar. Zuko says he had no choice, but Zhao tells Zuko he should have accepted his fate as a failure and a disgrace. Zuko continues to battle Zhao. Meanwhile, Iroh places the white fish back into the Oasis and then notices that Yue has been touched by the Moon Spirit. Yue decides it is her duty to give the life she was given back to the Moon Spirit despite Sokka’s protests. She places her hands on the fish transferring her spirit, exhaling one last time and then falls back into Sokka’s arms – no longer alive. The Ocean Spirit heads out into the open ocean and attacks the Fire Nation ships. Yue’s body disappears, the white fish begins to glow and Iroh places the fish into the Oasis. The fish begins to swim and the Oasis glows as the spirit image of Yue appears above the water to tell Sokka she will always be with him. Her spirit kisses Sokka one last time before becoming the Moon. The Ocean Spirit sees the Moon is back and then places Aang atop a piece of the outer wall and then heads back into the Water Tribe city. Zuko and Zhao continue to battle when Zhao notices the Moon has returned and shouts “It can’t be!” Just then the Ocean Spirit grabs Zhao and begins to take him away. Zuko tries to help but Zhao stubbornly refuses to accept Zuko’s hand. Zhao is pulled into the water and disappears. Master Pakku announces plans to head to the South Pole with other tribe members to help rebuild the tribe there. Katara asks about Aang’s training and Pakku tells her Aang will have to get used to calling her Master Katara. Chief Arnook quietly tells Sokka about the vision the spirits gave him when Yue was born about a young woman giving her life to become the Moon. Sokka replies that he must be proud. The Chief says he is proud, and sad. Iroh slyly says is surprised Zuko is not at that moment trying to capture the Avatar. Zuko declares he is tired and Iroh soothingly tells him he should rest as “A man needs his rest.” Zuko closes his eyes. Katara meets up with Aang and they embrace. Momo jumps in as Sokka takes hold of Aang’s shoulder and Appa shows up as they all look out at the moon realizing they managed to ward off the Fire Nation and there is still hope to restore balance. Back in the Fire Nation, Fire Lord Ozai ominously gives Azula an undisclosed task.
