The episode begins with Aang awakening on a Fire Nation ship. Upon seeing the Fire Nation tapestries hanging in his room, he panics, believing he has been captured. He flees his room and runs into two guards—who turn out to be Pipsqueak and The Duke, two former members of Jet's Freedom Fighters. Aang attempts to flee, only to find himself crippled by his wounds. He eventually finds himself greeted by his friends, as well as Bato and Hakoda, all clad in Fire Nation uniforms and cloaks. Overwhelmed by this whole situation and weak from his wounds, he faints.
The scene switches to Zuko watching the moon until he is approached by Mai. He reveals his conflicted feelings about his internal changes and his imminent return to the Fire Nation. She tells him not to worry, and kisses him before leaving.
Meanwhile, Katara informs Aang that he has hair now, and she also tells him about how they had returned to Chameleon Bay after he was injured. They had found her father, and later captured a Fire Nation ship. Hakoda greets Aang and tells him that though the Fire Nation has captured Ba Sing Se, they would still go ahead with the plan to invade the Fire Nation on the Day of Black Sun. In an angered tone, Katara corrects him that it is Sokka's plan. Aang begins to feel pain once more and returns to his room with Katara to undergo healing. While she is healing his back, Aang begins to recall the battle in Ba Sing Se and feels that he has failed everyone as the Avatar, that he was more than hurt by Azula's lightning attack but that his spirit had actually separated from his body, and that if Katara hadn't healed him he would be dead. Katara says that she used the spirit water on him, not knowing what exactly she did; Aang says she saved him. They return outside again as daylight begins to break, as Sokka explains that the Earth King and his bear, Bosco, had decided to travel the world in disguise. He mentions that they have currently gotten through the Serpent's Pass. According to Sokka, although their forces are greatly outnumbered for the invasion, they have one clear advantage - the world believes the Avatar to be dead, and thus the Fire Nation will not be hunting for him any longer. However, Aang does not take this revelation well at all, because this marks the second "death" of the Avatar.
On the balcony of the Royal Plaza in the Fire Nation, Lo and Li announce the capture of Ba Sing Se, as well as the return of Prince Zuko and the death of the Avatar to the assembled armies below. They explain how Azula instructed the Dai Li to bring down a small section of the wall to allow the Fire Nation army to enter unopposed. Afterwards, soldiers are seen marching through the streets, and platoons of Fire Nation tanks roll towards the Earth Palace, amongst the Earth Kingdom citizens shown are Iroh and Zuko's former employer Pao, Jin, and Ying and Than with their baby, Hope. Both Azula and Zuko appear to the crowd to rising cheers to the armies. The scene then switches to the front of the crowd where a man is smiling up at Zuko and Azula. he looks much like Ozai except younger with shorter hair.
Meanwhile, Aang and the others run into an actual Fire Nation ship. While the others hide, Hakoda and Bato try to talk their way out, but the crew eventually finds holes in their story. The Captain decides to let them think they got away, but sink the ship as soon as they are clear. Toph overhears the order, however, and swiftly drops the captain and his guards into the water by way of Metalbending. Katara then puts space between the two ships with a huge Waterbending attack that nearly capsizes the enemy ship, and they try to escape. Despite the tremendous efforts of Katara and Toph, the ship takes heavy damage from the pursuing Fire Nation ship. Out of sheer bad luck, the Serpent of Serpent's Pass appears but is struck by a stray fireball. The heroes get the chance to escape as the enraged serpent attacks the Fire Nation ship.
The scene changes with Zuko at the palace, feeding Turtle Ducks like he once did with his mother, until Azula steps in to ask him why he looks so depressed. Zuko tells her that he does not want to see his father yet because he did not capture the Avatar. Azula reassures him that the Fire Lord should not care because the Avatar is supposed to be dead. She then asks him suspiciously if he thinks the Avatar is still alive. Zuko warily recalls the Spirit Oasis water that Katara had showed him, along with its special healing abilities, but he tells his sister that the Avatar could not have survived. Azula gives him a suspicious look and tells him that their father wants to see him.
Fire Lord Ozai congratulates his son on a job well done and even mentions that he feels especially proud that Zuko showed ferocity in how he killed the Avatar. Zuko asks him what he heard about this, and his father responds that Azula told him that Zuko had slain the Avatar.
Azula was seen with the man in the crowd briefly. They walk around the palace and kiss before they take different paths.
Later that night, Zuko confronts his sister pointedly as to why she said he killed the Avatar instead of telling the truth. She answers that she wanted to make him feel better and to let him have some of the glory. However, she also implies that, should the Avatar be found alive, whoever was responsible for not killing him, would face Ozai's wrath. In essence, Zuko is her scapegoat.
Docking at a port, Aang confesses to Katara he feels ashamed that everyone thinks he is dead and that he failed to stop the infiltration at Ba Sing Se. After giving into a burst of rage, he asks Katara to leave him alone. She reluctantly leaves him to gather supplies in port. While his friends are away, he flees the ship in hopes of infiltrating the Fire Nation alone. He makes it far, even passing a blockade of Fire Nation ships, before a storm picks up. He then uses a log in the water combined with his glider to make a sail-surfer.
Katara returns to Aang's room only to find it vacant, she immediately realizes what has happened and rushes out of the room. She runs to her father telling him, in tears, that Aang has run away to fight alone. She then pours her heart out to her father about the entire situation of the war and how she has missed him. Hakoda comforts Katara, and tells her that he has missed her and Sokka every day since he left, and not a day went by that he did not think of them. He says that he would sit awake at night thinking about them so much that it ached.
Meanwhile, the storm becomes even more intense, with Aang ultimately losing his glider. Aang feels like a failure, thinking that he will not make it out of the storm, but Avatar Roku appears to him in a vision, apologizing for not doing anything to stop the war before it began, and encouraging Aang not to give up. Princess Yue also appears in a beam of moonlight, calming the ocean, offering her encouragement as well. With Yue's help, Aang makes a huge tidal wave and heads off, washing up on Crescent Island, where the Fire Temple once stood.
His friends find him lying on the shoreline, having split up with the Water Tribe warriors until the attack. They tell him that they intend to travel with him, as they still need to continue his Earthbending training. Toph finds his broken glider and returns it to him. Aang decides that if he is to maintain the element of surprise, the world will have to think he is dead for the time being. He then impales the glider into the molten rock, leaving it to burn.