As the newly extended gang strives to reach the mysterious Western Air temple, we find that they are now forced to walk as Appa is not able to carry all of them for extended periods. Tired and disheartened, they all share their worries and woes as they walk. The foul mood is broken as Toph smiles and says, "Hey, we're here!" The group is confused as all they can see is a canyon. But Aang reassures them that she's right. The Western Air Temple has very special construction...it's built on the underside of the cliff, with upside-down buildings exotic stone arches and fountains.
We shift to the point of view of Zuko, humbled and fresh-faced, he ascends into the canyon a few moments before the gang. As he takes in the view, he flashes back to his first visit to the temple, 3 years earlier. He stands, with a fresh bandage over his left eye and argues with Uncle Iroh about his need to hunt down the Avatar and restore his honor. He labels Iroh "the laziest man in the fire nation". Coming back to his new self, Zuko hangs his head in the remembrance of the hurt he inflicted on his uncle. He ducks out of view as Appa soars into the temple.
Teo, Haru, and The Duke eagerly make plans to explore the temple. As Aang runs to follow them, Katara stops him. When Aang protests she tells him that as the avatar he should stay with Toph, Sokka and herself to discuss what to do next. Aang pouts throughout the meeting as Sokka and Katara suggest that they should return to the idea of finding Aang a fire-bending teacher. Aang distresses that there is no one. Katara suggests Jeong Jeong and Aang becomes sarcastic and rude. Toph starts to ask for back story on Jeong Jeong but stops herself, grumbling that she'll find out soon enough. Aang abruptly ends the meeting to go unwind with some flying.
We find Zuko living in a small wooded area just above the temple. He has made a tent from his Fire-Nation air balloon. He comically stumbles through a practice speech, trying to find a good way to introduce himself to the gang, but can't seem to get past the fact that he's spent years hunting and attacking them. He tries to self-advise himself by impersonating Iroh and then Azula. He gives up and decides to just go and see them.
Katara, Toph and Sokka follow Aang through the sky on Appa trying to convince him to land so they can continue the discussions about fire-bending. Aang pretends he can't hear them and opts show off his flying. As they eventually land, Toph alerts them to the fact that Zuko is standing close by. Nervous, Zuko utters, "Hello, Zuko here..." They all sink into battle stance as he continues with a weak introduction, "I heard you guys flying around down here and thought I'd just wait for you..." Appa breaks the awkwardness by recognizing his hero [Lake Laogai Episode] and licking Zuko from head to toe. Aang notices this as the others launch into their verbal attacks. Zuko apologizes for the past several months but Sokka and Katara are relentless in their denial of him. Zuko's new-found humility helps him to survive the onslaught as he offers to teach Aang fire-bending, apologizes again and reveals that he was the one who rescued Appa. He eventually appeals to Aang, who has stood silent this whole time. After looking over the anger in his friend's faces, Aang tells him that he can't be trusted and that he will never join them. Katara nixes another protest by Zuko by waterbending a fountain of water at him.
Zuko retreats to his make-shift camp and kicks himself for not being able to convince them. "Telling them I sent an assassin after them?! Why didn't I just tell them Azula did that? They would have believed that! Stupid!"
Aang, Katara, Sokka and Toph vent while they make up their beds for the evening. Katara brings up how Zuko was able to make her feel sorry for him while they were in prison together. Aang confesses that Zuko was the one who saved [Blue Spirit episode] him from Zhao's clutches several months earlier. Sokka and Katara convince him that Zuko only did that so that he could take the glory for capturing the Avatar. When they continue to bash Zuko and cast around doubts that he was the one to rescue Appa, Toph interrupts to say that Zuko was not lying. When the others start to argue again, Toph she speaks up to remind them of the real issue. Aang needs a fire-bending teacher and fate drops one in front of them and they denied him. She thinks that Zuko deserves another chance. They insists that they will find another way and should not even entertain the idea of Zuko as a friend or teacher. Toph storms off, "I'm beginning to wonder who's really the blind one here."
Zuko sleeps while something rustles the bushes nearby. As the noise grows closer Zuko's gut instinct is to fire-bend in the general direction. Toph screams and throws up an earth wall as she tells him who it is. She cries in panic as she finds that her feet are burned, leaving her completely blind. Zuko tries to help her but in her panic, she uses a pillar of earth to throw him far away. He screams endless apologies and bangs his fists on the ground, appalled by what he's done.
The next day, Katara is serving rice to Teo, Haru, The Duke, Aang, and Sokka. She wonders aloud about where Toph is. The three new friends volunteer to search the temple. As they leave, Toph blindly breaks through a nearby wall. She explains that her feet are burned and that she can't see. As they tend to her, they ask what happened. She reluctantly tells them that Zuko burned her. She insists it was an accident but the group is already making plans to hunt him down and capture him. As they argue, we see that Combustion Man is back. He's tracked them to the mysterious temple and is watching them tend to Toph and argue. As he takes a sniper's aim at Aang's exposed form, Zuko swings in on a vine and knocks Combustion Man to the ground. Zuko shouts orders at the hired assassin, threatening to withhold payment and when that doesn't work, he offers to pay him double just stop. As the gang takes cover, Zuko continues to bargain with the assassin. When that doesn't work, Aang watches Zuko become Combustion Man's new target, knocking him off the cliff, into the abyss. Shocked, Aang launches into action, using new moves to form a tornado and kick it at the assassin. Luckily, we also see that Zuko is climbing a vine back up to the temple, no worse for the wear. Combustion Man dodges and jumps down into the temple as Katara attacks and the gang retreats behind a building. Toph tells them that the damage Combustion Man is causing is going to blow the temple right off the cliff side. Sokka's boomerang is their only hope. He gauges the scene and flings his weapon out, striking Combustion Man's third eye. Through blurred vision, the assassin tries to bend at them one last time but implodes instead, blasting a crater into the temple. He's gone for good as his metal arm flips down into the abyss.
Zuko finishes his climb up the vine and meets up with the entire gang. Aang thanks Zuko for his help. Zuko apologizes again and better explains himself to the gang and asserts his desire to help end the war. He bows to Toph and apologizes again for burning her. He explains that fire is wild and dangerous and admits a need to be more careful with it in order to stop hurting people unintentionally. This strikes a chord with Aang. He tells Zuko of the time he burned Katara and announces that he believes Zuko is meant to be his fire-bending teacher as Zuko understands the need for control to prevent causing harm to people they love. He also knows about the discipline Aang will need to master. Zuko and Aang bow. Aang asks the gang if they agree. Toph and Sokka are ok with it. Katara begrudgingly agrees for the benefit of Aang.
Sokka takes Zuko to his new room inside the temple. As he walks away, he admits that the whole thing feels a little weird. As Zuko unpacks a sketch of Uncle Iroh, he flashes back to the end of the conversation he'd had with Iroh during the visit to the Western Air Temple 3 years earlier. Zuko insists that his destiny is to capture the avatar but Iroh reminds him that destiny is a funny thing and that he must keep an open mind and open heart if he wants to find his way. As Zuko returns to the present, he finds Katara standing in his doorway. He stands and offers a humble smile but she only scowls. She enters the room and stands only inches from his face as she speaks to him. She tells him that she knows he's struggled with doing the right thing in the past and that she'll be watching him. She threatens that if he slips up even once, or if she even thinks he's a threat to Aang, he won't have to wonder about his destiny anymore as she will end him right then and there. She storms off, leaving Zuko to reflect on everything that's happened.