"Fire Lord Ozai is no more. Just as the world will be reborn in fire, I shall be reborn as the supreme ruler of the world. From this moment on, I will be known as ... the Phoenix King."
— Ozai to Azula.
Aang prepares himself to fight Fire Lord Ozai, but has difficulty deciding how to defeat him without taking his life. His friends push him, urging him to kill the Fire Lord, but Aang insists it goes against his beliefs. In his sleep, Aang is drawn toward a mysterious island that appears suddenly in the sea. His friends find June, the bounty hunter, to attempt to locate him again. Fire Lord Ozai crowns himself Phoenix King and Aang awakens on the unknown island now in the middle of the sea.
At the Fire Lord's beach house, Aang is practicing his firebending while Zuko watches and demands more ferocity from him. At first, Aang makes a feeble attempt at a particular move, but does much better with the next attempt. Everyone else is lazily sitting on the steps of the beach house. Katara prepares watermelon juice for everyone, causing Aang to excitedly abandon his training to get a drink. An angered Zuko criticizes them all for being lazy. Sokka and the others, except for an annoyed Zuko, head to the beach to have a party.
Katara uses waterbending to surf on the waves, while Aang and Toph make sand sculptures. After Sokka makes a hideous sand sculpture of Suki, Zuko appears and attacks Aang ferociously, scaring everyone. He chases Aang off the beach and back into the house. Once cornered by Zuko, Aang airbends Zuko out of the house, and everyone else comes to see why Zuko attacked Aang senselessly. Zuko angrily asks how they can relax and have a party when Sozin's Comet is arriving in three days. The others reveal that they believe that the Fire Nation already won the War after conquering Ba Sing Se, and that Aang can just wait until he has fully mastered the elements to defeat the Fire Lord, after the comet passes.
Just as Katara says that it could not possibly get any worse, Zuko grimly replies that it will. He tells them of the day before the eclipse when he attended a war meeting, where he was glad his father had finally accepted him back. The people in the meeting discuss rebellions inside the Earth Kingdom that must be stopped. Zuko explains the nature of the Earth Kingdom's people; they are strong and proud as long as they have hope. Hearing Zuko's words, Ozai believes that they must destroy their hope, and Azula suggests burning down the Earth Kingdom. Ozai accepts this idea and decides to use the power of the comet to crush the Earth Kingdom, just as Sozin himself used its power to wipe out the Air Nomads one hundred years prior. With this last piece of resistance gone, he could rule the world unopposed.
As the gang displays their horror at this news, Zuko concludes that Aang will have no choice but to defeat Ozai before the comet comes, otherwise there will not be a world to save. Aang is extremely downhearted by this news and feels overwhelmed. His friends, however, suggest that they will fight alongside him to have a better shot at defeating the Fire Lord. With Aang comforted, the gang joins together in a group hug, including a reluctant Zuko.
Later, Zuko teaches Aang the technique of lightning redirection. Zuko explains that though being able to hold such energy is exhilarating, one wrong move could prove fatal. Aang thinks Katara would still be able to heal him if that happened, but she says she used up all of the spiritual healing water when Azula shot Aang with lightning before. Zuko stresses that against an opponent as vicious as Ozai, Aang has no choice but to take his life. Aang anxiously replies he will do just that.
Sokka makes a dummy, naming it the "Melon Lord", to use as practice for the group's strategy to take out the Fire Lord. The rest of the group, except Toph who acts as the Melon Lord's forces, creates a diversion to provide Aang with the opportunity to deliver the finishing blow. During training however, Aang fails to finish off the puppet, saying it did not feel right because of his peaceful nature. Irritated, Sokka slices the puppet's head in two to show Aang how it is done, leaving Aang nervous and worried.
That night as they eat dinner, Katara finds a picture of a cute baby in the attic and shows it to everybody, thinking it is Zuko. Much to everyone's surprise, Zuko corrects Katara, noting that the picture is of his father, not him. When Suki states that Ozai looked cute, he adds that the cute little baby grew up to be "a monster" and a terrible father. Aang argues that even though Ozai is a terrible person, he was still a human being and should not be killed. Seeing all life as sacred and trying to think of another way to defeat him, Aang suggests to make large pots filled with glue, so he could use "gluebending" to stick Ozai's arms and legs together, preventing him from bending. To poke fun at the idea, Zuko adds that they could subsequently show Ozai his baby pictures to him in order to trigger his good side with all the happy memories. When Aang excitedly asks if the plan would work, Zuko snaps at the Avatar that it would not. Aang starts to restlessly pace around, musing that killing goes against everything he learned from the monks. Sokka jokes that as the Avatar, the universe would probably forgive him for taking a person's life if it was done in the name of keeping balance. Furious, Aang berates everyone for not being able to understand the position he is in and he storms off. Katara starts to follow him, but Zuko suggests he be left alone to figure the problem out himself.
Aang meditates on the beach house porch, accompanied by Momo. He and Momo later fall asleep, and with the sudden appearance of a strange small island off shore, Aang is unconsciously drawn toward the island with Momo flying after him.
The next morning, the others prepare to leave the beach house, but they cannot find Aang anywhere. They check the beach and find his footprints in the sand, leading into the wide open ocean. They deduce Aang did not run away, as his glider and Appa are still at the house; that he was not captured, as there was no sign of a struggle; and that Aang is not on a Spirit World journey, because his body would still be with them. They decide to split up to search Ember Island. Before they search, Toph states that, "Everyone else has been on a life changing journey with Zuko; now it's my turn", and she goes with Zuko. The search is futile, as no one finds Aang, and they additionally realize that Momo is gone as well. Sokka believes Appa has eaten Momo and comically climbs into Appa's mouth. They all look to Zuko as a leader, as he is an "expert on tracking Aang". Soon they are all flying on Appa toward the Earth Kingdom.
Meanwhile, preparing for departure with a grand ceremony at the Royal Plaza, Fire Lord Ozai orders Azula to stay in the Fire Nation to be appointed the new Fire Lord. Initially angered to learn she will not be accompanying her father, Azula eventually concedes that the title of "Fire Lord Azula" "does seem appropriate". Ozai subsequently declares himself the Phoenix King, the ruler of the world, and departs for the airshipbase.
Back in the Earth Kingdom, Zuko leads the group into a tavern where they find June, a bounty hunter, who has a shirshu which can track Aang. Somewhere else, Momo wakes Aang up, and Aang sees with great surprise he is on a mysterious island in the middle of the sea.
The war meeting that took place in "Nightmares and Daydreams" is revealed in full in this episode, also revealing the event that triggered Zuko's decision to betray his father and join Aang.
Colonel Shinu, the commander of the Yuyan Archers, makes a reappearance in this episode. Although addressed by Ozai as General, the credits still list him as Colonel Shinu.
General Bujing, the high-ranking officer whom Zuko called out during the war meeting which ultimately led to the prince's banishment, is seen in the War Room during Zuko's flashback exchanging an uneasy glance with Shinu.
In the beginning and throughout this episode, Toph wears her Earth Kingdom uniform, but for the brief section of clips when Zuko tells Aang to roar like a tigerdillo, Toph is seen wearing her Fire Nation disguise. Toph is also shown in her Fire Nation disguise while she is on her "field trip" with Zuko. This also occurs with Katara shortly before Sokka claims that Appa must have eaten Momo.
When Zuko is "teaching [Aang] a lesson" by attacking him, he chases him up a rock wall. Although it looks like he is clutching onto rock ledges or footholds as he climbs, there were really no ledges he could grasp onto.
When Sokka tells Zuko that Aang is not ready to face the Fire Lord, Aang's eyes are blue. His eyes are supposed to be a dark gray color, and when Sokka is yelling at him for refusing to take out the Melon Lord, his eyes are brown. His eyes change color multiple times throughout the episode.
During the scene where General Shinu is giving his report to Ozai on the Earth Kingdom rebellions, Ozai is seen from behind, and the central prong on the Fire Lord's headpiece is facing the wrong direction.
In the group hug scene, right before Zuko joins, Aang's left foot does not have any toes.
Due to a translation error, in the French version of the episode, Zuko says that his uncle created the lightning redirection when he learned waterbending, which is impossible, instead of saying that he studied waterbenders.
When Aang sleepwalks to the "island" he is barefoot, but when Momo wakes him up he is wearing shoes.
When Katara and Suki are looking for Aang, they see actress Aang circled by people, but actor Toph is not there. He then appears out of nowhere.
After Ozai tells Azula that she will be remaining in the Fire Nation, Ozai is seen from behind, and the gold trimmings on his robes are missing.
When Ozai tells Azula that she is not coming with him to the Earth Kingdom, all the people who bowed to them before disappear, but when Ozai crowns himself Phoenix King, everybody returns to bowing to him.
In Avatar Extras, it said that Zuko was the first person to find the Avatar after he went missing for a hundred years, though this is not true as Katara and Sokka were the first to find Aang.
There are times when Sokka's sword is the color of a regular sword rather than the usual black.
The chanting that can be heard when the Island/lion turtle calls to Aang, causing him to sleepwalk/swim to him, is a Buddhist chant, "Na Mo A Mi Tuo Fo" (spellings vary) and can also be heard during "Winter Solstice, Part 2: Avatar Roku", when Zhao and his soldiers are about to attack Aang, as well as in "The Siege of the North, Part 2" when Aang goes into the Avatar State and walks into the pond.
Sokka's terrible sense of aesthetics is shown once more. Here, he creates an ugly sand sculpture of Suki which he is extremely proud of, despite its hideous appearance.
During the bar scene, June is seen fighting a man who she throws into a table; this character bears a striking resemblance to "Ryu", the protagonist of the "Street Fighter" game series. She arm-wrestled the same guy in "Bato of the Water Tribe".
Though everyone else is in their season three outfit, Toph and Sokka are in their season two outfits, except in the part where Toph searches for Aang with Zuko, when she is wearing her season three outfit. Also, Katara switches between both of her season three outfits throughout the episode.
This episode has the longest recap, due to the fact that this is the first part of the series finale. Viewers are reminded of the many cliffhangers and plot twists that are to be resolved during the four-part series finale. However, in other appearances of this episode, "The Legend So Far" has been shortened.
This episode is the first part of the two hour movie, Sozin's Comet, which pulled in an average of 5.6 million total viewers and achieved the highest Avatar rating ever with kids 6-11 and teens.
Toph suspected that Katara and Haru had a thing for each other, which surprises the entire gang.
The order in which Sokka mentions the elements is the order in which they are in the Avatar Cycle.
For the first time in the four part series finale, a secondary issue is raised in importance before Aang's well being. When asked what is going on, Sokka first points out that, "Zuko's gone crazy! I made a sand sculpture of Suki and he destroyed it!" Waiting a few moments before saying, "Oh, and he's attacking Aang."
At the end of "The Western Air Temple", Katara warned Zuko that she would not hesitate to kill him if he were to hurt Aang. She had forgiven him in "The Southern Raiders", so she might have decided to wonder why he attacked Aang this time rather than retaliate.
The passage of power from Ozai to Azula over the Fire Nation is very similar to how emperors would manage their home nation when given the title as Holy Roman Emperor in the Medieval Era. At the time, the Holy Roman Empire was considered the largest collection of power in the European Sphere.
This is the second episode in the series where all the members of Team Avatar have worn swimsuits, with "The Beach" being the first. It is the first time Suki has worn a swimsuit in the series.