When the group lands in the Spirit World for a rescue mission, they come face to face with dangerous threats, painful memories and a mysterious entity.
The Avatar serves as the connection between the physical and spiritual worlds. He hears when both humans and spirits are in pain. He must stop and take action. He is tasked with making impossible decisions. He knows an imminent threat is targeting the Northern Water Tribe. He doesn't have any details. He's impressed with the progress Katara has made in her training. She has grown quite skilled as a waterbender. Aang hasn't devoted himself to learning the same skills. Instead, he agonizes over the past. That informs who he is. He is over a century old. However, he wasn't present for most of that time. He was asleep. He couldn't restore balance. Many communities have suffered because he couldn't step up as the Avatar. He ran away. He can't avoid his responsibilities any longer. People are scared. The Fire Nation soldiers impose that dread everywhere. They aren't the only threats that terrify people. The spirit realm also holds creatures in agony willing to take out their suffering on those who cross the barrier between the worlds. Aang must ease that pain as well.
It takes awhile for Aang to cross over to the spirit world. He takes Katara and Sokka along for the journey. He doesn't know how he did it. They were initially tasked with protecting his physical body. He's defenseless when he's in the spirit world. Instead, the roles are reversed. Aang is tasked with saving his friends. It's dangerous for them to be in the spirit world. They can't escape from the fog as easily as Aang can. They get lost in their memories. The fog exposes them to their darkest truths and fears. It's absolutely daunting and paralyzing. The pain consumes them. They aren't safe so long as they follow the path. They only run into more danger. It's not entirely the fault of a monster hellbent on consuming their souls. The spirit of the forest is suffering because of the destruction the Fire Nation troops caused to create a more convenient path. Katara offers Aang the reassurance that the forest will regrow. The area will be full of trees once more. It's hard to see that in its current state. It requires people to have faith and see what's happening under the surface. Aang plants the seeds out of respect. That's not the extent of his mission though.
Both Katara and Sokka are taken to influential moments within their family. For Katara, it's the day her mother was killed. She has been haunted by that moment for a long time. However, more details are provided as to what happened to Kya. The Fire Nation attacked because they feared a waterbender was living amongst the tribe. Katara had already proven her powers. She had no control over them. She couldn't use her skills to stop the invasion. She couldn't use them to save her mother. Instead, Kya confesses to being the one the soldiers want. That results in her death. She sacrifices herself to save her daughter. Meanwhile, Katara is full of rage and regret that she wasn't strong enough to save her. Kya and Gran Gran talk about Katara being destined to protect the entire tribe. They know her strength. Others feared it. That invited the destruction in. Meanwhile, it's personal for Sokka. His vision isn't of the day his mother was killed or when his father left. Instead, it's the day of his ice jumping trial. He was tested by the leaders of the tribe. He passed. Hakoda marked him with the symbol of wisdom. Yet he privately confesses that his son disappointed him and nearly got everyone killed. Sokka overheard that truth. He's eager for his father's approval. That's because he fears he never had it. He wants to be a great warrior. His journey is his own now. He's out to prove a point. Yet his father isn't around to see any of it.
Aang isn't distracted by the vision of the Southern Air Temple in all its former glory. He understands it isn't real. He doesn't fall into the trap laid out by Koh. The spirit is looking to add to his collection of faces. He will feast on the souls of this who have fallen prey to the fog. Aang only has a short amount of time to save his friends and the nearby villagers. He also discovers something unexpected in the spirit world. After death, Gyatso refused to move on to the next stage of enlightenment. He knew Aang still needed him. And so, he resides in the spirit world to continue offering guidance. Aang laments not having his greatest teacher around anymore. Gyatso understood the severity of the burden placed on Aang. He also left plenty of room for fun. That's the perfect balance for life. He reassures Aang that leaving was the only thing that saved him. If he was at the temple when the Fire Nation attacked, he would have died like the rest of the monks. The Avatar would have been lost for good. No hope would be possible for the rest of the world. He survived for a reason. He's now on the path to make a difference now. He just needs to remember what grounds him. That includes saving his friends. That's the mission. He must retrieve what Avatar Roku took from Goh. Restoring that balance may be enough to satisfy the vengeful spirit. It's a mission Aang must take by himself. It's dangerous because Roku's temple resides in the Fire Nation. It's what must be done.
Moreover, the entire world is now alerted to the return of the Avatar. Zuko wanted the news to remain secret. That was his only hope of being the one to capture him. He couldn't contain it though. Aang is making his presence known in the world. When he arrives in a new community, proclaiming himself as the Avatar is how he establishes trust. He has to back it up with his actions. He has done that so far. He could never avoid the countless troops targeting him and his friends. They have the skills to get away. Zuko is the most devoted hunter so far. He isn't the only one with a vested interest. Commander Zhao sees this as an opportunity to improve his standing in the army. Azula encourages her father to test him. He could prove to be a reliable partner in this endeavor. She's hot-headed and ambitious as well. She wants the honor of being the heir to the throne. Ozai continually proclaims Zuko as the one who made this miraculous discovery. That's enough to upset her. That's how she channels her rage. She's still training. She hasn't left the Fire Nation. She hopes to influence the hunt from afar. Meanwhile, Iroh hires a bounty hunter to help Zuko prevail. He wants the best for his nephew. Zuko is defeated upon realizing the entire world knows of the Avatar's return. He still has weapons in his arsenal worth exploiting. He just has to be comfortable using them even though they don't abide by his long-standing stance on right versus wrong.
