DISCLAIMER: ATLA is not my creation. I will use the characters to simulate situations/storys that could appear in the show.
The characters are copyrighted to Nickolodean and were created by Michael Dante DiMartino and Bryan Konietzko.
Prologue: Aang is training to open his chakras, so that he can achieve Avatar State at will. When he is close to accessing the Avatar State, he stopped by a vision of Katara in a prison, and in trouble. He immediatly leaves to rescue her, endangering himself and creating the possibility that he may never access the Avatar State at will. Katara after being ambushed by Azula, Ty Lee and Mai, is thrown into the crystal catacombs of the Old Bae Sing Sae. Azula after finding out about the existence of her brother and uncle in the city, arranges them to have tea with the Earth King, secretly setting an ambush that works. She takes Zuko as prisoner and puts him in the same prison as Katara...
Katara, gasped and whirled around at the sound of the entrance to the catacombs of crystals in which she was imprisoned, opening. She heard the Dai Li throw the prisoner into the pit. She stared as a familiar figure rolled to a stop and went into a kneeling position in front of her.
She gasped as she recognized Zuko! "ZUKO!" She gasped.

"Why did they throw you in here?!?" She shouted at Zuko's silent back. "Wait lemme guess, it's a trap! So, that when Aang comes to help me,
you can finally have him in your little Fire Nation clutches!" She continued.

Zuko just glanced at her before turning his back again.

"You're a terrible person, you know that? Always following us, hunting the Avatar, trying to capture the world's last hope for peace!" She ranted.

Zuko was silent.

"What do you care? You're the Fire Lord's son, spreading war,violence and hatred is in your blood!" She continued in a bitter tone.

"You don't know what you're talking about!" finally answered Zuko, breaking his silence.

"You think I don't?!?" shouted Katara, enraged that he had finally answered, turning violently to glare once more at his back. "How dare you! You have no idea what this war has put me through!" She said her voice trembling with emotion as she remembered the hard memories.
"Me personally!" said Katara, starting to cry as she crouched trying not to let Zuko see. "The Fire Nation took my mother away from me." She said softly and bitterly.

Zuko turned his head, his expression full of pity and understanding."I'm sorry." he said, softly as Katara wept into her arms, crying from her rant and the memories. Zuko turned to face her. "That's something we have in common"

Katara paused in her sorrow, when she heard those words. She was surprised that she and Zuko, Fire Prince Zuko, epitome of all that was wrong with her life, the world, had anything in common. She slowly wiped her tears. She turned and stood. "I'm sorry I yelled at you before," she said regretfully, now that she knew Zuko understood what she felt in losing her mother.

"It doesn't matter," said Zuko, lamely, trying to be comforting.

"It's just that, it's been so long now, that whenever I've imagined the face of the enemy, it's been your face..." said Katara, softly,
her words full of regret and remorse.

"My face..." said Zuko, softly, and conciously touching his scar from the Agni Kai with his father, Fire Lord Ozai.

"No, no...that's not what I meant..." said Katara, realizing what he had thought of her words.

"It's ok, I used to think this scar marked me, the mark of the banished Prince, cursed to chase the Avatar forever. But lately I've realized that I'm free to determine my own destiny.Even if I'll never be free of my mark." said Zuko.

"Maybe, you could be free of it." said Katara, thinking of the water of the Spirit Oasis at the North Pole, that Master Pakku had given her upon her departure.

"What?!?" said Zuko, turning around, shocked at the idea that he could be freed of the scar that had been with him for years.

"I have healing abilities." said Katara, growing confident that Zuko had changed for the better, and willing to help complete his change, by freeing him of the mark that chained him to forever be bitter.

"It's a scar." said Zuko flately, convinced that he would never be free of it. "It can't be healed"

Katara reached into her robe and took out the vial containing the water.
"This is water from the Spirit Oasis at the North Pole. It has special properties, so I've been saving it for something important," said Katara as she walked up to face Zuko. She held it out to him, "I don't know if it'll work, but..." She stared into Zuko's face, as he stared back at her. He closed his eyes as if signaling he wished to be healed.
Katara placed one hand on his scar, she bent towards him. This is close enough to kiss him, she thought. She used her teeth to pull open the stopper on the vial and called out the water with her power. The water encased his scar glowed and then, faded.
Katara bended the water back into the vial and stepped back, taking a look at Zuko.

Zuko's eyes were still shut.

And then, he opened them...