On an air ship within the fleet, Toph Metalbends the rudder to make the ship spiral into the others. A Fire Nation soldier on the ship spots them and tries to blast them off. They evade his attack only to fall off. Sokka tries to break the fall using his sword, but instead lands on a platform which breaks his leg. Toph is left dangling off the edge, holding Sokka's hand. Two Firebenders approach to attack them on either side, so he uses his boomerang and sword to ward them off, losing them both. Even so, more Firebenders come, and Sokka and Toph are seemingly doomed. They are only saved by another incoming air ship crashing into the one they are on. They land on it and discover Suki was driving it.
Even though Aang is in the Avatar State Aang and Sozin both seem evenly matched. Since Sozin is barely able to counter The Avatar State's fierce bending, he is unable to land any successful hits himself, even with Sozin's Comet at his disposal. Sozin used 5 fire whips out of his 4 limbs and his mouth as he shot them at Aang. Aang dodged the attack and created 5 fire whips of his own. Sozin recreated his 5 fire whips and attacked Aang like crazy. He then stopped his fire whips and continued to duel the Avatar.
In Ba Sing Se, the Order of the White Lotus is successfully liberating the city. Bumi takes down several Fire Nation tanks and Iroh burns down the Fire Nation flag on the Earth Kingdom palace. The Order of the White Lotus then finishes the liberation of the city before finally getting the chance to rest.
After an excruciating duel Aang in the Avatar State proves to be too powerful and too quick for Sozin. Aang got tired of seeing Sozin evade all his attacks, resorted to a ruthless barrage of all four elements being thrown by the Avatar State. Sozin evades the elements until he can evade no more, and uses fire to deflect the last one to Aang's surprise. Aang takes advantage of Sozin's fatigue and sends a blast of all 4 elements at Sozin while he recovers. Though Sozin manages to stop most of the attack with a fire blast, he is blasted off of the top of the rock and falls helplessly towards a shallow lake below. Using Fire out of his feet, Sozin barely manages to save himself from a fatal fall. Sozin looks up and sees Avatar State Aang swiftly approaching, eager to resume the fight. Sozin is overwhelmed and shoots as much fire as he can muster at Aang to give him some time to escape. Aang uses a combination of all 4 elements into 1 attack to counter Sozin using an extremely powerful jet of White Fire. The result is both opponents are thrown away from each other. Sozin got the worse part of the blow.
Back at the Fire Nation capital, Azula relentlessly shoots fire and lightning at Katara and drives her away from any water. She taunts Zuko, who is collapsed on the ground. Though Katara finds water to bend, Azula is too quick for her to attack and is forced to flee from her immense flames. Eventually she discovers chains and water underneath a grate in the plaza, and lures Azula above the grate. She traps herself and Azula inside a large splash of frozen water barely a second before Azula was going to blast her. Katara unfreezes the water around herself, swims around and binds Azula's hands together to the grate with the chains. She releases the water and runs to Zuko to heal him. Zuko weakly thanks Katara, and she says she should be thanking him for protecting her. Azula sees her brother rise unharmed, and starts Firebending wildly with her breath. Zuko and Katara ignore her and they run toward Appa as fast as they could, despite Zuko's injury. Zuko and Katara get back on Appa and go back to Wulong Forest as fast as Appa could fly.
The contact between Sozin's and Aang's fire streams created such a loud explosion that Sokka, Suki, and Toph heard it from the air ship way behind them and looked over. They were all wondering who got the worse part of the explosion. They hoped Aang protected himself enough to survive.
Aang, still possessed by the Avatar State, continued to pursue the Fire Lord and tried to crush him between two stone pillars with Earthbending, but Sozin managed to stop himself in time. Sozin tried to counterattack, but Sozin's attempts continuously failed against the Avatar's unbelievable power. Aang caught Sozin with Waterbending and subdued Sozin with Earthbending shackles onto Sozin's arms and legs.
Aang then stated with the voices of all the previous Avatars that "the Fire Nation has devastated the balance of the world, and now you must pay the ultimate price: death."
The possessed Aang proceeds to deliver the final blow, a combination of all four elements into one attack but hesitates as Aang tries to regain control. That attempt by Aang fails but his attempt allowed Sozin enough time to escape the shackles. Sozin fell on the ground and Aang finally gained control over himself.
The duel was so long it gave Katara and Zuko enough time to travel on Appa in an effort to assist Aang, but they were just a minute to late.
Sozin smiled as Aang turned his head. Sozin jumped off of the platform and kept himself up in the air with his Firebending. Aang did not notice Sozin jumping off, and turned around to see Sozin flying in front of him. Aang looked up in shock and fear as Sozin shot a lightning bolt at him. Aang caught the lightning bolt and prepared to redirect it at Sozin, but Sozin did not let up on shooting his lightning bolt at Aang. The lightning built up in front of Aang and he could not redirect any of it out of his body. Sozin did not stop shooting lightning until Aang could not hold it any longer. The lightning exploded in Aang's face and electrocuted him, thus killing him in an explosion that was so bright even Toph knew what happened.
Sokka looked over at Aang and Sozin in shock. He knew Aang was dead and told Toph and Suki about it. They saw Katara and Zuko and Team Avatar retreated from Wulong Forest as Sozin looked over at them. Sozin shot 5 simultaneous fire blasts at the airship, destroying it, but he did not attempt to chase down Appa. Instead he retreated to the Fire Nation airship base. Sozin knew Zuko went to fight Azula and he wanted to go check on Azula.