Chapter One
Out of everyone in the gang, Katara is the one person who can consistently surprise Zuko.
She surprised him with her fiery passion when he had her tied to a tree. She surprised him with her skill as a waterbending master once she found a teacher (i.e. that time she kicked his butt in the North Pole). She surprised him when she offered to heal his Uncle after Azula's lightning strike. She surprised him when she opened up to him, was vulnerable, and offered to try and heal his scar.
What surprises him the least is when she threatens him after joining the gang. It hurts, sure, but he knows he deserves it (and Zuko is an expert at finding ways he has failed). He works extra hard to earn her trust back, helping with chores around camp, pushing her out of the way of falling rocks, before finally going on a field trip he's certain he'll never forget.
(He's surprised again, to learn about her bloodbending, but at this point all it does is further prove that Zuko absolutely did the right thing by joining the gang.)
What surprises Zuko the most, however, is how much Katara opens up to him after she forgives him. Maybe it shouldn't surprise him, maybe he should have realized this was always meant to happen, he was always meant to be there for her, and his betrayal in Ba Sing Se only delayed the inevitable.
She no longer fights his offers to help with chores, but accepts and maybe even comes to rely on his help. She no longer holds back her laughter when he makes terrible jokes (and he knows they are terrible, so he's surprised she's even laughing, but maybe she has the same terrible sense of humor). She no longer frowns every time she catches him looking at her. Sometimes she even smiles.
Zuko does everything he can to help her out because somehow he's the only one who sees how much all the mothering she does for the group is truly weighing on her shoulders. He doesn't realize it until later, years later, but there's something about taking care of Katara that is almost healing for him.
He does laundry with her, helps cut up vegetables for meals, starts fires for cooking, makes tea to go with dinner (and whenever Katara has trouble sleeping), carries Toph wherever she wants (even though she has long forgiven him for burning her feet, he knows that it keeps Toph out of Katara's way when she's mending), and spars with Sokka and Suki to keep them from hanging all over each other in front of Aang and Toph.
(Years later, when he's being honest with himself, he might realize he did it for Katara, so she wouldn't have that look of hurt and sad and rejection every time Sokka and Suki's PDA got out of control.)
In the moments when they work together, they talk. She tells him about growing up with Sokka, about her Gran Gran, about having to fight Pakku just to be able to learn waterbending. Her voice has a wistful tone to it when she shares these memories, like she wishes she could go back, back to a time when all she wanted was to learn to waterbend. When she talks about her mom, he can hear the guilt she's processing over knowing her mom sacrificed herself to keep Katara safe. He talks about his mom, because he's trying to process the guilt that's been hiding in his subconscious since his mom disappeared. It's just another layer to the tragedies that bond them.
When Katara starts talking about her dad, her voice has an edge that wasn't there before. It's the same edge that creeps in whenever she talks about Aang's habit of disappearing. It isn't until the day of the comet, when they are flying towards a destiny he's still not ready to face and she tells him Aang has to come back, that it clicks for him.
Katara has unresolved abandonment issues.
He doesn't have time to process this, what it means, how he can help her, because suddenly they are landing and he's fighting his sister for what he knows will be the last time.
(He doesn't even think, not really, when he jumps in front of that lightning. All he can think about is saving Katara).
In the week of Katara-mandated bedrest before his coronation, he has plenty of time to think, and he decides on a simple solution. He wants Katara to know he will always be there for her, and somewhere in his lightning-rattled mind he decides that means Katara should always know where he is.
(He doesn't let himself think about the option of her staying, of her staying with him, because Katara deserves the world and he can't- won't hold her back from it.)
And for two and a half years after the war ends, he makes sure to tell Katara where he is at all times. When the gang is together, for peace summits or missions fighting rebels or when they finally, finally, find his mother, he simply tells her before anyone else if he has to split off or what his schedule is. When they are apart, him back in the palace and her traveling with Aang, he writes to her constantly. Their letters pick up where they left off in Ember Island, talking about their pasts, but also what they are doing, who they are meeting, how they are both doing their best to work towards peace in this world. In his letters, he makes a point to tell Katara if he's planning on leaving the palace, and when and where he'll be going.
(He tries to ignore the hints in her letters that suggest Aang is leaving her feeling alone, abandoned even, now that he has his fan club, because the last thing his heart can take is thinking about why Katara chose Aang over him.)
It seems to work just fine for those two and a half years, but Zuko should have realized Katara would have caught on eventually. And that's how he ended up getting yelled at, in his office, on what was otherwise a beautiful day.
Officially, Aang, Katara, and Sokka were visiting to negotiate trade deals between the Southern Water Tribe and Fire Nation. In reality, Sokka wanted to visit Suki and Aang heard the circus was in town. Zuko managed to take one day off from his Fire Lord duties to join them at the circus, but the next day finds himself buried in paperwork in his office. He skips lunch and eats dinner in his office. Just when he finally thinks he's gotten the mountain of documents down to a hill, he hears a harsh knock on the door. Before he can respond, Katara is already barging in, whirling about in her anger. Zuko panics and immediately inventories the water in his office, ready to hide under his desk if need be.
"What the hell, Zuko?!"
He clears his throat, and goes for the diplomatic approach.
"Good evening, Katara, is there something I can assist you with?"
"Yeah, you can quit treating me like your personal secretary!"
He winces. He certain she knows, but he can't stop his mouth from spewing, "What do you mean Katara? I don't understand."
"WHY DO YOU ALWAYS TELL ME WHERE YOU ARE LIKE I'M SOME KIND OF SECRETARY?!"
A/N: So I saw this post on tumblr post/633444541574332416 ages ago talking about Katara's abandonment issues and how in light of that, Kataang doesn't make sense. Me being the Zutara trash that I am thought "well of course Aang wouldn't notice, but you know who would? ZUKO" because if this boy could figure out she had connected her anger over losing her mom to her anger at Zuko then he can pick up on her issues. See also post/633439508744077312/kataras-abandonment-issues-zuko-comes-back and post/633444646672121856/do-yall-ever-think-about-how-katara-shared-the for more examples of Zuko being there for Katara. So anyways, he's still a dumb teenage boy so the way he tries to help Katara isn't necessarily the most thought out, and that's how this happened. Hope you enjoy!