Change
It should not matter so much to Zuko, that Katara forgives him.
It does anyway.
Zuko feels that he has been standing under a mountain all this time. Now, he thinks, he understands how Aang can be so free and light. Katara's acceptance means everything; is everything.
He wishes he knew why.
Katara feels relaxed, now. She does not need to watch Zuko every moment. He understands, she thinks. He understands what vengeance is, and he understands that she couldn't. Katara imagines that he might even understand why. He acted like a friend, when he took her to find Yan Rah. He supported her until she had what she needed. Katara wonders if he would have stopped her if she had been able to continue.
It doesn't bother her as much as it should, that she thinks he wouldn't. Aang would have, she knows. But Zuko would have let her take that path. And he would have helped her live with herself afterwards. So her intuition tells her.
Zuko has learned an infinite number of things from his field trip with Katara. He knows that their greatest object on the path to victory is Aang's pacifism. He knows that Aang and Katara are both far better people than him. He would not have hesitated to kill Yan Rah. But have Katara hold her hand with ice daggers only millimeters from Yan Rah's throat, he understands why he should. He hopes that he regains that compassion-for-its-own-sake someday.
Zuko is awed by that in Katara. In the Avatar, for all the inconvenience to their quest, it seems fitting, but Katara has it too. It seems to him a miracle that such compassion could exist in her side-by-side with such a dangerous power as her skill with Waterbending. He imagines what his father, or Azula, might do if they controlled someone with the skill to do what he witnessed Katara do to the captain of the Southern Raiders. He doesn't even know exactly what she did, but it was terrifying. And beautiful. It is not without a certain morbidity that he notes that Katara fighting; Katara who is not spending her time mothering Aang and the rest of the group; is stunning.
This revelation makes it impossible for Zuko to sleep. He rises with a silence born from his flight across the Earth Kingdom, his time masquerading as the Blue Spirit. Zuko has no particular destination in mind. He lets feet take him where they will, and so makes the full tour of their cleaned-up and modified corner of the temple until he arrives before Katara's door. With a sigh, he folds himself into a sitting position, intent on meditating.
He falls asleep.
Katara is not sure what has woken her. It feels too early to wake for breakfast—she still feels the impression of the moon under her skin. Gathering moisture from the air, she cautiously opens her door—
—and finds Zuko, curled up around his sabers. For a moment, Katara feels her old suspicion revive. She quells it, however. He doesn't look malicious, even if he does have his swords to hand.
An idea comes to Katara. Stepping out of range of his swords, he carefully directs her bubble of water over Zuko's head, and allows it to splash down on his face.
Zuko wakes up spluttering, swords drawn, and Katara can't help but giggle.
He glares at her in reply. "What was that for?" He sheaths his sabers.
Katara schools her face into a stern expression. "Care to explain why you were armed and sleeping outside my door?"
Zuko flushes.
"Couldn't sleep," he mutters. His voice dropped further. "Kept…thinking…"
"About?"
Zuko flushes deeper. "Just leave it, will you?" He snarls.
Katara can't help teasing him. She takes a step toward him. "Aww… Zuko…what could you have been thinking about?"
She did not predict the next part of the exchange.
Zuko thinks he will go mad. She is wearing next to nothing—only the white wrappings she wears for Waterbending training—and she is standing so close! He does the only thing he can do to keep his sanity.
He kisses her.