In the Earth Kingdom, Sokka states that he recognizes June as the bounty hunter who tracked Aang before. June is non-plussed at seeing Zuko again, but asks what he wants. He states that he needs to find the Avatar again. June doesn't seem interested in finding him, but agrees to do so. Katara bring Aang's staff for June's shirisu, Nyla, to track. However, Nyla is unable to do so. June states that the Avatar no longer exists.
Meanwhile, Aang wonders where he is. He thinks he is in the Spirit World, but successfully airbends and realizes that he cannot be.
Sokka asks if Aang is dead, but June denies it, as she could track him if he were. June attempts to leave, but Zuko stops her. There is someone else who can stop the Fire Lord: Iroh, and Zuko brings back an old slipper for Nyla to track. The group travels all night towards the walls of Ba Sing Se.
Aang, meanwhile, has come to a clearing. Extremely confused, he realizes he can call upon Avatar Roku for guidance. He mediates, and the spirit of the former Avatar appears. Roku cannot offer insight as to where Aang is, but he states that he knows Aang has a moral dilemma.
At the walls of Ba Sing Se, Zuko's group is asleep, but they are awakened to find themselves surrounded by a wall of flames. A group of people come to meet them. However, Katara and Sokka recognize them as old comrades: Master Pakku, King Bumi, Master Piando, and Master Jeong Jeong.
Aang explains his problem to Roku, that he doesn't know if he can take Ozai's life. Roku responds that, in his lifetime, he tried to keep such discipline, but Fire Lord Sozin took advantage of his mercy. Roku laments that, if he were more decisive, he could have ended the war before it began. Roku's wisdom to Aang is to be decisive.
Toph asks who these people are, and Katara responds they are old masters and friends of theirs. She bows respectfully to Pakku, who tells her he is their new grandfather. Katara is happy that he and Kanna are happy together. Katara introduces Zuko to Jeong Jeong, and Sokka greets Piandao again. Suki asks how all of these people know each other, and Piandao explains that they are all members of a secret society that transcends national borders, which Zuko recognizes as the White Lotus. Jeong Jeong explains that a call came out about a month ago from a Grand Lotus, Iroh. King Bumi notices that Momo is missing, to which Sokka responds that he is with Aang. The group heads off to meet Iroh.
Aang asks for help from the Avatar before Roku, Avatar Kyoshi. Kyoshi responds that she fought Chin the Conquerer, who threatened the bring the world out of balance. Aang responds that she did not kill Chin, as he fell to his own death. However, Kyoshi responds that she doesn't see a difference, as she would have done whatever was necessary to stop him. Her wisdom to Aang is that only justice can bring peace.
As Sokka walks through a canyon to reach the White Lotus's encampment, he asks Bumi how he escaped Omashu. Bumi responds that he escaped during the eclipse. He used his earthbending to escape the metal cage he was in, and then moved entire houses and a statue of Fire Lord Ozai to remove the Fire Nation's army. When Bumi asks if anyone else did anything interesting during the eclipse, both Sokka and Zuko claim they did nothing special.
Aang attempts to call another of his past lives, and speaks to Avatar Kuruk, the Avatar before Kyoshi and a Waterbender. He states that he was rather passive as an Avatar, and let people sort out their own problems. There was peace in the world, but Kuruk lost the woman he loved to Koh, the Face Stealer, because he wasn't attentive and active. His advice to Aang is that he must actively shape his own destiny, and that of the world.
At the White Lotus encampment, Piandao directs Zuko to Iroh's tent. Zuko is apprehensive about meeting Iroh. He believes that Iroh hates him, as Zuko turned his back on him. Katara attempts to cheer him up, and Zuko enters Iroh's tent. However, Iroh is asleep at the time.
Aang is still unsure of what to do about the Fire Lord. He decides that speaking to an Air Nomad will be beneficial, as they will understand his positions. He calls to the spirit of the Avatar before Kuruk, Avatar Yangchen, a female Airbender. She acknowledges his belief that all life is sacred, and that the monks have taught him well, but the world is more then just about him. Aang says that he was taught to detach himself from the world and be free, but Yangchen contradicts and says that the Avatar can never do such a thing, as he has a duty to the world. Her wisdom is that his duty will cause him to sacrifice his spiritual needs. He must do whatever it takes to protect the world. Aang becomes resigned to the idea of killing Ozai.
Iroh awakens the next morning, and notices Zuko there. Zuko begins his apology, but is interrupted by Iroh's hug. Zuko is confused as to why Iroh is so quick to forgive, but Iroh responds that he was never angry, just saddened that Zuko might have lost his path. Zuko states that he did lose his path, but Iroh returns that he found it again, and he found it on his own, and that he found his way to the White Lotus.
Aang awakens, and notices that some mountains in the distances are getting larger. But he realizes that instead, the island he is on is moving. He dives into the water to find out the reason, and finds that the entire island is the back of a large creature that swims in the ocean.
At the White Lotus campsite, Zuko claims that Iroh must come with them, as, other then the Avatar, he is the only person who can defeat Ozai. Iroh refuses, and states that, even if he could defeat Ozai, history would just see the conflict as a brother murdering another to gain power. Only the Avatar can end the war properly. Zuko next asks if Iroh will reclaim his rightful place as Fire Lord, but Iroh refuses. The new Fire Lord must be an honorable idealist: Zuko. Zuko protests that he has made too many errors, but Iroh states that, despite this, Zuko has always held the path he believed to be just, and only he can restore the honor of the Fire Nation, just as he restored his own honor. Toph worries that Aang will not return, but Iroh states that he will, because all of their destinies are upon them. Iroh reveals that his plan is to re-take Ba Sing Se for the Earth Kingdom, thus, the reason why he gathered the White Lotus. Iroh tells Zuko to return to the Fire Nation, so that he can claim the throne after Ozai falls, but Azula will be waiting for him. Iroh states that he'll need assistance to fight her. Zuko affirms, and chooses Katara. Sokka asks Iroh what he is to do, and Iroh returns that question by asking Sokka what he himself believes to do. Sokka responds that he believes he should stop the airship fleet, and Toph agrees, stating that they can back Aang up if necessary. Toph, Suki, and Sokka ride a giant eel-hound to the airship dock on a small island east of Ba Sing Se. Katara and Zuko board Appa to return to the Fire Nation capital, while Iroh reveals his plans to re-open his tea shop after he conquers the city.
Aang attempts to discover the true nature of the island he is riding on, and discovers that it is a lion-turtle, an ancient beast. He asks the lion-turtle for advice, to which it gives the advice that darkness has always existed, but always does it yield to light. The lion-turtle then places Aang on the shore, and tells him to wait for the Ozai.
Fire Lord Ozaii awaits the comet, ready to purify the world in fire. Elsewhere, Aang stands on a plateau ready to meet him. The comet comes closer to the earth and bathes the sky in red light.