"So Zuzu, you've managed to steal my rightful place as heir. I challenge you to Agni Kai!"

In the end, rather than fight for a city she already controlled, Azula met Zuko outside the city walls. She wanted to defeat him without him getting one foot in Ba Sing Se. They stood on a makeshift battlefield.

"I'm the oldest, Azula!" Zuko answered back.

She scoffed, "since when has that mattered? So is Iroh and he sits alone and drinks tea while our father conquers the world!"

"He had mom kill his father for the throne."

Azula laughed, "I know. Not only that she used her weakness against her—you. I was so happy when she was banished. She was so weak and pathetic."

Zuko frowned at her. "I accept your challenge. It's for the city."

She laughed, "one of us will be dead, Zuko. It's for the throne one day." She smirked and added, "and know your whore lives not five minutes more than you do." She paused and cocked her head. "No, I think I'll tie her down and let Mai cut her up. She can slowly torture her to death. She has to get some reward since I'm killing you."

Katara backed up but stayed within the makeshift arena. She was shocked at the sheer magnitude of the force of the battle between Azula's red fire and Zuko's blue fire. It was stunning and brutal all at once. She then realized her lungs were stinging because she was holding her breath.

She didn't realize as she was watching Zuko and Azula locked in blazing combat, Azula was tracking her. Azula turned and the moment came, when she gathered lightning to strike out. At the last minute she turned and smiled and struck out at Katara.

The smile had made the difference in two areas for Zuko. One it gave him just enough warning to jump in front of Katara and attempt to redirect her lightning strike. The other difference was flaming hot fury.

Katara screamed out in agony when Zuko collapsed, and a crazed-looking Azula went after her immediately.

Katara couldn't redirect lighting, so she dove out of the way of each lighting bolt directed her way. She was scrambling to figure out what to do.

Katara knew her secret was about to come out. She was a Waterbender, and she would have to use it against Azula. So she faced Azula, holding chains and taunting her.

Azula quickly moved to strike her with lightning, but when she was about to unleash it, Katara threw up her arms, bringing up water from the drainage system below them, and freezing them both in place. It was then apparent how close she'd been to killing Katara. Her fingers were pointed directly in her face. Katara then breathed out and melted the water where she was. She then moved with the chains and melted the water as she went. She chained Azula's now freed arms and chained her down, and dropped all the water back through the grate below them.

In a rush, Azula let out a crazed scream and struggled against her chains in vain. "Waterbender!" She screamed. "Kill her!"

Her eyes were full of fury when neither Ty Lee nor Mai moved against her. "I said kill her!" Still they didn't budge.

Katara heard none of it. She was cradling Zuko to her body, pulling water to her and trying to heal him. When he groaned out in pain she cried tears of relief. She finished healing him, weeping over him.

He cupped her cheek, "I'm okay."

"Why did you jump in front of me? We could have lost everything! You have to live, Zuko. You are what this world needs." She was lost to wracking sobs after that.

He gathered in his arms and kissed her tear tracks. He looked her in the eyes and said, "I'm a shell of a man without you. The world has to have us both or I don't want this world."

He then stood and looked at his crazed sister. She was spitting and cursing at Ty Lee and Mai. She was promising to kill them and rip their eyes from their bodies for betraying her.

Zuko sauntered up to his sister, he then looked back at Katara and with dry eyes she noticed the look in his eyes. They held fury, hatred, and burning anger. "Can you still accept me?" He asked Katara.

With tears continuing to pour, she nodded. "I accept all of you, Zuko. I love you."

He turned back to Azula who was still struggling against her bonds and trembling with crazed furry. He said, "your mistake was trying to kill the woman I adore. You were going to live."

He turned to Kyo, "unlock her chains. This isn't done yet; we're both still alive."

Kyo looked at Katara as he went to unlock a now subdued and smiling Azula. Katara looked calm to him, so he did as he was told. Once he did, he got out of the way of the coming battle.

Azula screamed in a crazed fury when Zuko was able to strike out first. She was out of her mind and didn't notice the difference in his eyes. Before, he fought to subdue; now, he was going for the kill. She had pushed him too far, and his anger was intense.

Red and blue flames arched out, clashed, and mixed together. Everyone had to step back as the battle grew wilder and more fierce. Azula couldn't help but laugh every time she tried to strike out and kill him.

Zuko managed to bend a flame that forced her back and made her stumble. She was embarrassed and incensed. His anger intensified while in her crazed state she didn't even hide that she was going to try to strike Katara with lightning again. This time he stepped in front of the woman he loved and redirected the lightning perfectly –right into Azula. She was killed by her own lightning bolt.

Sweat was pouring off Zuko as he stood on the now silent combat field. His sister dead, his lover safe –it was over.

He noticed Katara was standing by his side. She took his hand in hers and laced their fingers together. "Thank you for protecting me –again."

"Always. You know that."

"I do."

He sighed, "I don't know how to feel."

"Good. This should be complicated. You're a good man. I can't be impartial on this, Zuko. You saved my life. She wanted me dead, and she wasn't going to stop. I don't want to leave you. I want to stand by your side."

He turned and kissed her. "I vowed to protect you. I won't fail you."

"You never have."