A/N: Hi all, I originally published this under the title By The Light Of The Moon, thinking that it was going to be a cute little collection of Zutara one-shots. Then it kind of started running away from me, and now it's turned itself into a multi-chapter fic which is going to extend way past the end of the series. The original title/premise just didn't feel like it fit anymore, so I'm re-publishing in a way that feels right.

To those of you who are new to this fic, welcome! To those who have come from the old version, welcome back (the first six chapters are exactly the same, no need to re-read, unless you want to)!

Disclaimer: None of the characters in this fic are my own creations, they belong to Bryke/Nickelodeon. I've also used some dialogue from the show at multiple points - basically if you recognise it, it's not mine.

This first chapter takes place during The Southern Raiders, so get ready for some angsty Katara and trying-not-to-be-angsty-anymore-but-sometimes-failing-spectacularly Zuko.

Instinct

The sound of cracking stone rends the air between them, followed swiftly by a medley of soft clinking noises as the first small pieces of debris start to fall.

For a split second, somehow detached from the danger around him, it strikes Zuko that it's a strangely benign sound to herald the collapse of their temporary home. But collapsing it is, and he's pulled brutally back into the moment as the ceiling begins to give way above them.

She's standing there, staring half-horrified and half-resolute at the now-shuddering doors of what had seconds ago been their sanctuary. Katara hasn't realised yet that the sky is falling – it seems no one has other than him. Maybe it's his knowledge of Fire Nation attack strategies guiding his gaze in the right direction, or maybe it's just sheer dumb luck that he hears what no one else seems to, but whatever the reason he knows what he knows.

She stands, unfaltering, unaware.

And he runs, throwing Suki to one side away from the fracturing ceiling as he launches himself at Katara.

Hanging there, suspended for a moment in the air, Zuko somehow has the time to think that this was a really, really stupid decision – jumping into the path of what's probably a literal ton of falling rock in an attempt to save the life of a girl who openly hates him is... Well, it's an interesting choice. But he's made it now and it's not as if he can take it back, so he prays to every dragon of old that he has enough momentum to get them both through this without being crushed.

The impact knocks every reverent thought out of him as they land, clear, on the stone floor. The impetus that saved them reveals itself to be bittersweet as they skid and roll across the rough ground, his body wrapped hard around hers doing only little to shield her from the blows.

They scrape to a stop feet away from the pile of rubble which would've ended her. He aches as though he's just been stampeded over by a sabre-tooth moose lion, and it's only going to hurt more later on, but she's safe under him, her back pressed up against his chest, and she's...

'What are you doing?!'

Angry. Agni's sake, she's angry at him.

But, bizarrely, it doesn't matter that she still seems to hate him, seems to hate the fact that it was him who just saved her life. As he runs towards the light that glares through the splintered doors, he's left with the certainty that he wouldn't have done those few moments any differently. They feel as though they had been unavoidable, and he knows, as stupid a decision as it felt, that it hadn't really been a decision at all.

He hadn't even needed to think.

Her lungs squeeze in her chest as she makes sense of what Sokka is saying. No. No, she can't say goodbye to their father again, can't watch him walk away from them down that tunnel as if the world isn't already falling apart around them. Every time he leaves she's weighed down a little more by the thought that it might be the last time she gets the luxury of saying goodbye.

But Appa is unyielding behind her, and the sounds of the Fire Prince and his sister exchanging blows are a dogged reminder of the fact that they all need to get out, now. So she hugs him hard, eyes stinging and heart clenched, and turns quickly away so that this time she can be the one who leaves first.

They make it past Azula, the bitter heat of her fire flickering past them around Toph's rock shield, and Katara turns to see her figure shrink behind them, to make sure that the threat really has passed. As she watches, Azula turns, gaze drawn to the Fire Nation airship which is rising behind her. Her brother stands, defiant, jaw set, and Katara stares at the siblings in their confrontation.

It shakes something in her, watching them face each other like that. Without looking, she feels Sokka's presence behind her, and tries to imagine how it would feel not to have him as the steadfast support that he is; how would it feel to, instead, be locked into a bond so vicious that they could stare across a chasm of air and cloud and see only an enemy? The thought twists in her gut and she releases it quickly, focussing fleetingly on the bursts of blue and orange light that are now unfurling from the two firebenders below.

Her attention is torn away by the jolt of Appa sweeping into a sharp upwards turn, balls of flame soaring past them as they climb quickly up and over the top of the Fire Nation airship in front of them. Relief rushes through her, pulling her hair out behind her as they fall and curve over the other side of the vessel, swinging forwards towards open air and freedom.

But they are not the only ones falling, and he has no power to right himself.

Somehow, it doesn't feel forced. If she'd had minutes – seconds, even – to think about it, she definitely would've weighed things up more carefully first. It would never have been a question about whether or not she let him fall (because, let's face it, she just didn't have it in her to let someone die like that), so with all the time in the world to think about it, she knows she would've come to the same conclusion.

But, and here's the important part, it wouldn't have felt simple. She wouldn't have been particularly happy about saving the life of the boy who'd tormented them for so long. She would've been clear on every reason behind her actions, none of which would've had anything to do with a concern for him or his safety.

But as she flings out a hand to pull Zuko from the air, Katara doesn't need to think at all. And afterwards, when she does have the time to stop and turn it over in her head, it almost bothers her how easy it was.

For a moment, as the group laughs at his quip, Zuko almost feels like he's starting to belong, the thought knocked clumsily into place by Aang and Toph's friendly punches, tentatively soldered by the fire crackling in front of them.

Then her voice cuts through the cheer, a caustic echo of the voice in his own head that still tells him he's wasting his time.

'Yeah, no kidding.'

He doesn't understand. And not in a 'what did he ever do to her?' kind of way. He knows what he did, and how much he did; he knows what he has to repent for. But he's trying to repent, and all the others seem to be finding it easy enough to start welcoming him in now that he's shown them how much he means it. He doesn't get why she's so resistant to him, and he makes sure that she knows that.

'What is it with you?'

Then she answers, and suddenly he thinks that perhaps this isn't about his repentance at all.

Sokka's face tautens as he tells Zuko the story, more serious than the other teenager has ever seen him outside of battle. As he speaks, something flickers in the pit of Zuko's stomach; a strange, quaking feeling that feels a bit like nostalgia, only crueller, more nauseating. He doesn't push it away, instead pulling it up to stick firmly in his chest, and he holds it there until she comes out of her tent the next morning.

It's petty, she knows. But he's sitting in front of her and it's first thing in the morning and everyone knows that waterbenders are night people. She can't deal with him being right there right now, so yes, she reaches for petty, and she's unapologetic about that.

'You look terrible.'

'I waited out here all night.'

The thought does not endear him to her.

'What do you want?' Snapped, tightly. Because really, she doesn't care what he wants, she just wants him to leave her alone.

'I know who killed your mother.' Her heart stutters, hands stall. 'And I'm going to help you find him.'

Perhaps she should be asking him why he cares enough to help. Perhaps she should be asking him what he gets out of it. Perhaps she should be asking herself what she expects to achieve by finding this man.

But she doesn't ask. She doesn't dare.

He's enabling her, he knows. And he knows that this isn't really what she wants, this isn't really who she is. But hers is a feeling – hers is a rage – that he recognises. And he knows first-hand that it won't be touched by reason. It had taken him far too long to understand that this was why his uncle had facilitated all his reckless hunting; not because the old man ever believed Zuko's salvation was in achieving his goal, but because he'd known all along that it wasn't, and that his nephew would need more than just a few earnest words to see that for himself.

So when Aang tells her forgive the man whose memory has tormented her for six years, Zuko raises his eyebrows and twists his voice into something that sounds like derision. Never mind that he knows the younger boy is right.

Whatever choices Katara's going to make, she needs to make them herself. He's just giving her the opportunity to find out what they are. He hopes that she doesn't need as many chances as he did to get it right.

The moon had always been a comfort to her before now, even more so after Yue rose from the waters of the Spirit Oasis and took her place amongst the stars; tonight, though, it is cold and unfeeling as it rises above the water, Appa skimming over clouds bathed in the last light of day as it gives way to the night.

The Fire Prince is asleep, sprawled out in the saddle behind her. Or at least he was.

'You should get some rest – we'll be there in a few hours. You'll need all your strength.'

She bites back, rankled by his concern, but her own words open a dam somewhere inside her, and without meaning to she's telling him all of it, every detail she remembers of the final moments she had with her mother. As she speaks, something rustles at the fringes of her memory, something that feels like recognition, a moment of reflection in a scarred face bathed in pale green light.

She doesn't want it, and pushes it away with force as she reaches the end of her story.

'Your mother was a brave woman.'

Like she needs him to tell her that. But, she notices, she doesn't hate him for saying it as much as she would've thought.

They fight together well, each ceding for the other as they make their way through the boat, the need to communicate out-loud lost to something more instinctive.

His eyes widen as he watches her bend the body of the Southern Raiders' captain to her will, the man's joints popping as he tries to fight against her control, and for the first time Zuko is gripped by the fear that he's made an awful mistake, that he's led her down this path and now she isn't going to walk it the way he'd expected.

But he has led her here, trusting that she will do the thing that's right for her when it comes to the moment to choose. So he keeps trusting, and he keeps leading.

The heckled heron of a man studies the path behind him warily, calls out in uncertainty. It's all she needs to know that this time they've gotten it right. She doesn't know what she feels; something too complex to simply name it as anger or pain or anticipation. But then she sees the man's face tense in unease and it's the same face that she's seen in her nightmares, halfway between waking and sleeping, for the last six years.

Haunted. That's how she feels. And now the ghost is real.

He sees her breath catch, feels the rain intensify by the pull of the waterbender's emotions as Katara finds out the truth behind her mother's murder, her sacrifice. He barely has time to be impressed by her power before admiration makes way for awe; the downpour has stalled under her hold, gravity cowed by her wrath. She looks like she belongs on another plane, a spirit made solid by grief and fury, a Mu-onna forged in reverse. And for a moment it feels as though the storm itself is holding its breath, teetering on the blade's edge, waiting to see which way she will go.

She holds.

She launches.

She stops.

His hands are clenched into fists so tight that the rain is starting to hiss as it hits him, steam rising from his skin. He'd thought in a flash of stomach-turning, stunned panic that he'd read her wrong, that she was really going to do it.

As she releases the rain from her grasp, he loosens his fists and lets out a quiet, shaking breath, thanking every spirit he can name that this is the way she's destined to go, that her corruption will not be something that sits on his conscience tonight.

He'll take it to his grave that some small part of him – the same part that houses the sneering, snarling voice that taunts him when he's on the edge of sleep – pushes him in the direction of the snivelling man who still kneels before him, coaxes him to do what she couldn't, mocks him when he walks away leaving the man unscathed in the mud.

'I didn't spare him. Not really. I just... Couldn't do it.'

She needs him to know that she isn't merciful. She is not superior. She is not transcendent. She needs him to know that this doesn't feel like a victory. It feels sickening, rising in her like bile. She doesn't want to be glorified or praised for this, this failure that rasps in her throat.

'You wouldn't have been you if you had. But I understand why you wanted to.'

Two days ago – La, two hours ago – she would've rounded on him, asked who was he to tell her what kind of person she was, let him know in no uncertain terms that his understanding was not something she needed. But the grate in his voice sounds like the way her hands are shaking, and she thinks perhaps he really, genuinely does understand, and she thinks perhaps that is what she'd needed this whole time.

It doesn't make her feel any better.

That's the moment she forgives him.

A/N: And this can be the moment you forgive me for all the angst. Honestly, though, this is the only way that I could've covered this episode - it is not a happy day in Katara's life, and I wanted to hold off on any real inklings of feelings between them for this first one and focus more on them beginning to get each other. In my opinion, it's a really important set-up for things to get better later on. But having said that, I do promise that the next one will be at least a bit less heavy! Until next time!