Iroh, the retired Fire Nation General, looks at his nephew with a concerned, serious demeanor, having just arrived in the natural prison that he and Aang had journeyed toward to rescue him and Katara. "Zuko, its time we talked." He turns to Aang and Katara. "Go help you're other friends. We'll catch up with you." Aang walks through the hole from which he came. Katara follows after casting one worried look at a distressed Zuko. "Why, Uncle?" Zuko asks, his voice full of hurt and pain. " You are not the man you used to be, Prince Zuko." Iroh explains, "You are stronger and wiser and freer than you have ever been. And now you have come to the crossroads of your destiny. It is time for you to choose. It is time for you to choose…good." Before Zuko can respond, the catacomb wall explodes as Azula and two Dai Li agents burst through into the clearing. The Dai Li agents quickly trapped Iroh in a column of crystal. Zuko takes a fighting stance until the dust clears. Zuko stands between Azula and Iroh, eying Azula angrily.

"I expected this kind of treachery from Uncle, but Zuko, Prince Zuko…you're a lot of things, but you're not a traitor… are you?" Azula questions Zuko. "Release him immediately!" Zuko angrily retorts. Ignoring his outburst, Azula continues. "It's not to late for you, Zuko. You can still redeem yourself." Iroh retorts this offer. " The kind of redemption she offers is not for you." "Why don't you let him decide, Uncle?" says Azula, clearly irritated. She turns back to Zuko. " I need you Zuko. I've plotted out every move of this day, this glorious day in Fire Nation history, and the only way we win, is together. At the end of this day, you will have your honor back. You will have Father's love. You will have everything you want." Iroh desperately tries to reach Zuko. " Zuko, I'm begging you. Look inside your heart, and see what it is that you truly want."

Zuko stands, clearly conflicted. "You are free to choose." Azula replies before waving away the Dai Li and leaving to follow Aang and Katara.

Back in the waterfall cavern…

"We've got to find Sokka and Toph!" Katara says to Aang as they race through the cavern. Aang nods. Sensing danger, he earthbends a wall of stone behind them just as a blue streak of flame is about to hit them. The impact knocks Aang to the ground. Azula, whose fingers are still smoking from the blast, jumps down into the cavern. Katara quickly bends water from a nearby channel and sends it crashing down on Azula, who easily dissipates it with an explosion of blue flame. A moment later, she jumps out of the steam and launches two fireballs at Aang and Katara, who extinguish them both with a stream of water. Azula leaps on to a stone pillar. Using his earthbending, Aang quickly stretches his arms out, then brings them down, creating a shockwave that brings down the pillar. Frightened, Azula leaps from the pillar and lands between them, clearly nervous, when a blast of red fire hits the earth. Zuko leaps down fro the ceiling and lands in a fighting stance, facing Azula. Azula stares at him angrily, knowing she cannot defeat all three of them. Zuko then looks at Aang, who gasps before Zuko shoots a giant fireball at him. Satisfied, Azula attacks Katara forcefully. Aang makes an air shield just before impact. Zuko continues punching fire at him, a crazed expression on his face. Aang creates a person- shaped airwave and sends it at Zuko, who is blown back by the attack. He gets up and readies himself for another attack, then falters. Images of his mother, uncle and Appa flood through his mind before hearing his mother's voice, "Never forget who you are."

He closes his eyes, then reopens them. With new passion, Zuko turns around and launches a fireball directly at Azula. She only has time to duck as the fireball whizzes past her head. She looks at Zuko, who is standing next to Katara. "Fool!" She says angrily. "Uncle has gotten to you. You're weak and spineless and pathetic!"

Zuko's face remains stoic. "You're the fool, Azula!" He screams as they trade blows. "You're just daddy's little girl, aren't you!? You're only doing this to please him!" Azula snarled and unleashed a massive fireball at Zuko, who rolls out of the way before continuing. "What has he ever done for you? You're his puppet! You always thought you were his favorite. I did too, but he never cared what happened to us, as long as he got what he wanted. Think about it; he sends his 14-year-old daughter around the world to find and kill the most powerful bender alive. Does that sound like a loving father to you?" Azula's eyes open wide before she screams. "SHUT UP!" and launches a maelstrom of fire at Zuko, who managed to raise a wall of fire to deflect the bulk of the blast but was knocked back just the same. Zuko crashes into the crystals and falls down, unconscious. Katara simply stares at Zuko in disbelief until Aang runs over to her. "What happened? Why did Zuko attack Azula?" Katara turns to him. "He's changed." Aang's eyes narrow with suspicion until he is interrupted by A scorching fire blast to his right. Katara raises her arms and bends a wave at the distracted Azula, who is blasted back before getting up and gritting her teeth. Just then, the wall rumbled and collapsed as a hundred Dai Li agents surrounded Aang and Katara. Katara quickly summons water from nearby channel and fashions eight watery tentacles, but Aang knows there are too many. He remembers the Guru's words; "The only way, is to let her go." Aang closes his eyes. "I'm sorry, Katara," breathes with regret. He makes a tee pee of crystal and meditates. As he enters the Spirit Realm of the Avatar, the crystal tee pee begins to glow. The Dai Li and Azula watch, mesmerized.

Suddenly, the Avatar's eyes open, and the teepee is destroyed in a burst of spiritual energy. As Aang rises triumphantly in a column of light, Zuko awakens. He grins as he sees Aang rising. Suddenly, out of the corner of his eye, he sees his sister readying herself to shoot the Avatar down with lightning. Zuko quickly rushes over to her, and as she fires the bolt, Zuko jumps and catches it in his fingers. Katara watches him with awe. After holding the lightning, Zuko discharges the lightning back down at the Dai Li, dispersing them. Azula's expression quickly shifts from confidence to rage, but quickly turns to horror as the Avatar turns to look at her with an expression of pure fury. She tries to run, but the Avatar stops her, and with a flick of his hand, encases her in ice from the channel. He turns back to the Dai Li and fires a massive tornado that spins them around the cavern, smashing them into walls and the ceiling. Finished, the Avatar descends from his perch into Katara's arms, spent from the effort. "Katara," he says weakly. "What is it?" She asks. "With great power…comes great need to take a nap." He replies before falling asleep. Just then, Azula breaks out of the ice, and the Dai Li reorganize. With Aang unconscious, Katara looks up at the Dai Li, helpless. Just then, Iroh leaps down between Katara and the Dai Li

"I will hold them off. Go!" He says. "Uncle…" Zuko starts. Go, Prince Zuko." As Zuko prepares to leave, Iroh stops him. "Zuko… I'm very proud of you." He smiles. Zuko smiles back before Katara lifts them up on a water spout, out onto Appa, where they meet up with Sokka, Toph, Momo and the Earth King. "The Earth Kingdom… has fallen." He says dejectedly. " It wasn't a total loss," Katara replies. "Look who joined the group." She waves to Zuko. " Hey." He says shyly. Sokka shrugs as they fly into a moonless night.