A/N: I'm so sorry I fell behind on that weekly schedule I had going everyone. I'm going to do better, I promise.

xx-Kitten.

Brightest Nights or Darkest Days

By Kittenshift17

CHAPTER EIGHTEEN

Katara despised travelling on the Rhinos. It made her lower back ache and the saddle sent her rear numb and the constant sway of the waddling beasts did absolutely nothing for her cramps. For five days they had made good time, quickly closing the distance toward Ba Sing Se in large part thanks to the speed of the Rhinos and the fact that they didn't have to carry everything themselves, but Katara hadn't been enjoying the journey.

As she stiffly slid down from the saddle to land on the ground once more, Katara hissed and bent double when the sudden shift and twist on her internal organs caused shooting, stabbing pains throughout her midsection.

"Are you okay?" Zuko asked, frowning a little when he turned from beginning to unpack the saddle bags to set up camp for the night.

"No," Katara muttered.

The Firebender was angry with her thanks to the fact that she'd been in foul mood for days. Stuck in such close quarters, swaying along pressed against one another all day long aboard the Rhino, in combination with the fact that Iroh seemed to find perverse pleasure in discovering just how much Meng could actually talk in any given hour hadn't left either her or Zuko in the best of moods.

"What's wrong with you?" Zuko wanted to know, frowning at her slightly when she shushed him, not wanting Iroh, Kuzon and Meng to know that she was only suffering because of Moon-time.

"It's nothing, Zuko," she said, nudging him aside slightly to get at her pack.

"You've been saying that for five days," he argued.

"And I'll keep saying it until I'm not in pain anymore and this phase of the moon passes," Katara retorted, hoping he'd get the hint and recall the comment she'd made about the moon controlling more than just her bending.

Zuko froze as he watched her dig into a certain pouch within her pack – the only one she'd asked him not to ferret through whenever he raided it looking for the things she was carrying – and when he suddenly slapped his own forehead Katara glanced at him, startled.

"You could have just said something," he muttered awkwardly and Katara frowned at him even as he moved to stand behind her.

When he slipped his hands under the hem of her many layers of clothing – untucking several of them from her pants since their lack of physical exertion by walking themselves meant she'd had to rug up warmer, Katara frowned all the more. When he burrowed under her clothing far enough to finally reach her skin, Katara made a noise of impatience, thinking that this was definitely not the moment for him to be trying anything. Not that he'd tried anything during the past five days since they'd left the village behind. Beyond the kisses he'd pressed to her neck in the marketplace to hide his scar, he hadn't laid a desiring finger on her.

She opened her mouth to tell him that he wouldn't be doing so now either, unless he was actually interested in being covered in blood, but before she could say a word he smoothed his hot hands over her lower abdomen. Katara groaned, her head dropping back to rest upon his shoulder and her eyes drifting closed. Like a heat pack applied directly to the aching muscles, his hands felt divine, loosening some of her tension and easing some of the pain. She almost didn't want to move, though she was going to need fresh bindings if she didn't hurry.

Her whole body went boneless against Zuko's and he adjusted his weight slightly to catch her when she leaned back against him. Without thinking she smoothed her hands along his forearms to grip his wrists, adjusting his hold on her to better relieve the sorest spot and Zuko gave a little huff of amusement. She could feel his chi pushing against her just a little bit, warming her even more.

Opening her eyes slowly, she tilted her head on his shoulder to look at him. He met her gaze with one of those unreadable blank expressions that hid his emotions so very well, but his eyes glittered with sympathy and something else she couldn't name.

"Thank you," she murmured.

Zuko nodded, shrugging off the gratitude as nothing. Katara thought about informing him that no other boy she knew would react that way to realising a girl's moon-time was taking place. The one time during their travels so far when Sokka and Aang had figured out that she was so cranky because of her menses had resulted in them both suggesting to camp in the same spot until it was over as though fearing she might bleed all over Appa's saddle and Sokka had informed her that girls were disgusting, while Aang had tried for some kind of anecdote about using meditation to combat the bad feelings.

She'd almost murdered them both that day. She'd have thought that someone as unfamiliar with women as Prince Zuko, and indeed, someone who'd been raised as a spoiled, pampered Prince in a palace full of servants where she didn't doubt gender roles were strict and maintained, would be disgusted by the very idea that every month she and women the world over bled. When he'd spotted the supplies she'd stolen during their raid of the barracks he'd made faces and looked awkward when she'd tipped those things out of their sacks form the raid.

"How long?" he asked quietly.

"To go?" Katara asked. "Probably two or three more days."

"And then you won't be so cranky?" he asked and Katara might've blown up at him for the comment if he didn't sound genuinely curious, as though the effect of this time of the month was something wholly new to him that he was attempting to understand.

"With luck," she said. "Unless Meng keeps being so annoying with all that perkiness."

Zuko snorted with amusement at her snarky comment, suddenly seeming amused by her foul mood, rather than annoyed with her as he'd done for the past few days. She wondered if he'd thought she was grumpy with him over what they'd done in that hotel room. Since he hadn't tried anything like it since, she suspected that he'd thought she regretted it and was trying to push him away as a result.

"Can't you heal the cramps yourself?" he wanted to know.

Katara sighed, shaking her head. "I've tried. It's… uh… not wise. I can relieve some of the pain but attempting to 'heal' the underlying cause of the cramps is… messy."

Her cheeks flushed pink with embarrassment at the admission. She'd tried that just after she'd found out she could use her healing abilities, thinking it would be the perfect solution to suffering monthly cramps and aches. It hadn't gone well. Her magic worked by healing whatever the cause of pain was in the body, repairing any damage done or purging anything creating the problem.

Fortunately she'd been on the ground and by herself in her tent when she'd tried it, but that had been one of the most alarming nights of her life. In healing the cause of the pain – which was the slow stripping and shedding of her uterine wall after her ovum went unfertilised – she'd caused it all to 'heal' at once, the lining shedding at high speed and causing a gush of blood and tissue that had ruined her favourite bindings and her favourite sleep pants forever.

"Girls are gross," Zuko declared, wrinkling his nose at the very idea even though he didn't have any of the specifics.

Had Sokka or Aang said the same thing Katara might've been offended, but Zuko said it in such a way that she actually laughed instead.

"Don't say that so loud. Most girls would hurt you for suggesting that idea," she chided him, turning her face and burrowing her cold nose against the side of his neck.

"I think Uncle bought some willowbark tea, if you want some?" he offered.

Katara's lips twitched and she nodded before pressing her lips to his neck affectionately, the feel of his chi sliding against hers making her more comfortable. It had been doing so all day as they rode the rhino, but she realised that their moods and their intentions affected the way their chi interacted.

"Don't start that," Zuko muttered in her ear when she nuzzled his skin lightly, feeling suddenly affectionate and snuggly with him now that some of her pain was lessened. "We don't both need to be covered in blood, Water Bender."

"Gross," Katara snorted.

"Yes, that was my point," he deadpanned in return. "You go deal with your mess. I'll make you tea."

"I may lay claim to your hands when I get back," she warned when he turned his head slightly and dropped a kiss to the middle of her forehead, apparently not even thinking about the caring gesture.

"If you'll stop snapping at me, I'll let you put my hands wherever you like," Zuko replied. "This is why you've been cranky at me, right?"

Katara nodded, smiling a little bit.

"Alright. Well, next time say so," he commanded, sliding his hands back out from under her shirt and moving back a bit so he wasn't propping her up anymore. "I thought you were angry about what we did."

Katara turned to face him, tipping her head back slightly to meet his gaze when he eyed her through the rapidly growing darkness as evening fell.

"I'm not angry about that," she said quietly. "I'm worried about that."

Zuko nodded, obviously in agreement that the glowing and the breathing of fire and the fact that she still had a burn mark in the shape of his hand on her lower back that didn't hurt but wasn't healing either, were something to be concerned over.

"I haven't told Uncle," Zuko admitted. "I'm not sure if he would know anything about what happened."

"He probably doesn't. I get the feeling only other people who're part of a Reiki Kizuna would know – and probably only those who are a fire and water combination. And since your uncle said that the last known bond-pair were realised more than one hundred years ago, I'm not sure there's anyone who would be able to tell us. Maybe there's a library in Ba Sing Se where we could find out more until we find Aang?"

"There's probably something about them in the Fire Sage's temples in the Fire Nation, too. I could find out when I go home," he suggested.

"Yeah," Katara nodded. "But who knows how far off that will be?"

Zuko frowned a little, eyeing her strangely for a long moment before his hands lifted to curl around her jaw. Katara squeaked in surprise when he tipped her head up to meet his lips for a soft, tentative kiss. He didn't push it, he just brushed his warm lips over hers slowly and lightly, exploring, testing the effect. Her chi seemed to quiver against his and she knew she melted into the touch, kissing back just as carefully, as though holding something fragile she was afraid to break.

When he pulled back he was frowning again, his brow furrowed in thought and his thumbs traced across her cheekbones before he let his hands drop. Katara blinked at him, hating the way she wanted to burrow into his warmth and curl up in his arms until she felt better and until the world was a better place.

She didn't know what to make of it all and she'd been worrying herself silly over what their effect on each other in the bedroom had done, wondering if it had somehow linked them forever. She didn't know nearly enough about spirit magic or about Reiki Kizuna to hazard a guess and she had no previous experience at anything sexual with another Bender so she had no point of reference for what was normal between Benders and what was something else.

Grabbing the things to make camp for the night, Zuko gave her one more of those unreadable looks before turning away and moving off to begin setting up a fire-pit at the others in their travelling party began doing the same. She was still thinking about the problem when she returned from her potty break, frowning slightly as she used her bending to create a five roomed igloo for the night.

They had found that the rhinos were best controlled when they had somewhere to be out of the snow and the wind, even if it was inside an icy dome – and that giving the beasts a large fire-pit to gather around prevented them from crowding too close to the heat of their cooking fire. They'd learned that the hard way when the Rhinos had burst through the wall of the igloo on their first night while Katara had been cooking dinner. The meal had almost been ruined because the unruly Rhinos had all tried to stand in the fire-pit. They'd discovered that giving the rhinos something of a warm barn type structure to huddle in for warmth prevented such accidents. They'd also found that Iroh hadn't been kidding about his snoring and on the third night of their travels together even Meng had lost her perkiness in the middle of the night with the man's snoring, erecting an earthen wall to enclose the ice-wall Katara had made around the man just to block out some of the noise.

Zuko had found that entirely too funny, since he'd been putting up with his Uncle's snoring for years, but Katara hadn't been thrilled. When the structure for the igloo was set up – Meng not yet confident enough to make them something with her Earthbending that wouldn't crumble during the night – Katara went about making dinner. She smiled when Zuko appeared beside her mid-way through the chopping process and handed her a cup of willowbark tea.

"Thank you," she said, accepting it and smiling at the Firebender.

"Do you want to spar before dinner?" he asked her, his Uncle already in the process of furthering their combined instruction of Kuzon.

Katara pondered the idea for a moment, wondering if a bit of exercise might do her good to combat the crankiness and lethargy she was fighting.

"Alright," she nodded, setting aside the vegetables she'd been chopping, knowing she could always come back to them later. They'd all been snacking on jerky and nuts throughout the day so she doubted anyone would be overly hungry just yet anyway.

She accepted the hand up Zuko offered her, keeping hold of him as they both made their way outside into the evening. Iroh was pushing Kuzon through a basic warm-up of hot-squats and fire-fists, insisting Meng do the same. Without an Earthbending master among them, none of them could offer her proper Earth Bending instruction, but Iroh had studied many of the different Bending disciplines, so he'd been instructing her on some of the basics. Both Benders were improving, Kuzon faster than Meng, naturally, what with two Firebending masters to teach him.

While Iroh trained the two rookie Benders, Katara and Zuko moved a little further away to avoid hurting the others by accident before bowing to each other formally. Zuko smirked just a little as he straightened, his eyes still on her, before he struck the first blow. Katara dodged when he threw a rapid series of fireballs at her, pulling the snow to her to create a long water whip. She flicked it out at Zuko, wielding two at once and flicking his fireballs away with ease before striking at him, trying to hit him. He hissed at her when one of the whips curled around his ankle as he kicked an arched flame in her direction, yanking him off balance.

He shook it loose with a fire-blast and Katara smirked at him when he levelled a glare in her direction before stepping up the heat and the speed of their spar. When he evaporated her whips Katara began flinging shards of ice and ice-disks at him in rapid succession, smirking at him wickedly when she managed to hit him with a few that he wasn't fast enough to block when they came so fast and so thick. A wave of fire stopped them for a short moment before Katara decided that an up-close and personal fight might be in order. She did better fighting from a distance, she knew, but she needed practice in close combat fighting if she wanted to improve and she needed to be able to hold her own in instances where revealing herself as a Waterbender might be detrimental or dangerous.

Skating across the ice she wielded, Katara threw a series of punches and kicks at Zuko, blocking his return blows with her water whips and tentacle arms, interspersing the fight between hand-to-hand combat and Bending.

"You're going to break your wrist if you try and hit me like that again," he warned her, knocking one of her punches to the side before it could connect with his chin at a bad angle. Right at that moment she used her bending to lift him off his feet, flinging him up in the air and whipping him back toward the ground.

"It was a distraction," she smirked, having to cartwheel out of the way when he kicked fire at her on his way down. He landed tucked into a ball, rolling on impact and spinning low to get back on his feet, making her jump more fire as it arced out in her direction.

Katara slammed him with a tidal wave pulled from the melted snow around them, crashing it into him. He threw up a fire-shield but it didn't withstand the blow and he cursed when he was thrown across the clearing. He sprang up dripping wet and looking angry now. Katara flung more ice-disks at him, watching him dance as he dodged every single one while punching fire-blasts at her in rapid succession. She snarled under her breath when a few got through, scorching her training clothes and burning her skin.

When he closed the distance between them, Zuko tackled her right off her feet and they struggled, rolling and flipping across the ground, each throwing more punches and kicks, trying to get the upper hand. His superior strength found her pinned under him in the snow but before he could demand that she yield after pinning both of her wrists, she jerked her chin sideways, slamming him with another water blast that flung him off of her. Zuko came up mad as Fire-hornet, hissing and drenched, all the angrier when she froze him in place as she sprang to her feet. It didn't help for long when he breathed out hot air and the ice melted just as quickly. Just in time for Katara to throw herself at him and kick him in the stomach. He absorbed the blow by gripping her ankle and yanking her with him when he stumbled back, making her wince when the angle stretched her legs to an uncomfortable angle, twinging her hamstrings.

He jerked upwards on her leg and Katara snarled, jumping off the other foot and kicking him in the chest, back-flipping out of his hold and knocking him back another step. She nearly lost more of her hair when he flung more fire at her, trying to make her dance when he cracked the flame out like a whip. She hit him in the face with an oversized snowball without thinking and Zuko came up with a shout of fury, his eyes blazing with his sudden rage as the blow to his face triggered him.

Katara realised she was in danger, and that he'd been holding back, when he suddenly created an inferno of flames, throwing a twister of fire at her that almost pulled her up into it. She cursed, bending more and more snow around her body to protect herself and watching it all evaporate as the twister came closer. Just when she feared he might actually engulf her in flames Katara dodged around the flame and dove at him, tackling him off his feet and ceasing his control of the fire.

Zuko grunted and rolled, flipping her over his head and trying to pin her to the ground. They wrestled, scuffling in the dirt and trying to overpower each other. Katara narrowed her eyes on him when he pinned her, still too angry about the blow to the face to think rationally as he pinned her face-down in the dirt, arms trapped behind her back and one of his hands holding her head down so she couldn't bend while he straddled her lower body.

Her only defence left was her chi and Katara shoved with it, doing her best to encase his raging inferno of anger in ice. Zuko drew a shuddering breath when she squeezed harder, breathing out and managing to freeze his drenched clothing and hair stiff, preventing some of his movement.

"Zuko!" Iroh snapped. "Enough!"

Zuko wasn't listening and Katara shoved even harder with her chi, trying to bend through the Firebender on top of her. He made a strange sound in the back of his throat and went suddenly limp, his hand on her head lifting as water encased it and she used it to slap his right cheek with. Not that hitting him in the face again was the best idea.

"Get off, jerk," Katara said, bucking under him when he spluttered in shock both at being slapped by his own wet hand, and by the notion that she was pushing her bending power through him enough to do it.

His hold loosened and he lifted off her enough to roll her to her back. His eyes were narrowed slightly and he aimed a fist at her, waiting for her to yield. Katara eyed him in return, annoyed that he'd managed to pin her but not ready to give up the fight just yet. Reaching for him with one hand, she offered a small smile, letting him think she was going to touch his cheek.

"Ouch!" he growled when she grabbed a fistful of his hair and yanked him sideways off of her, rolling until she pinned his wrists over his head with her hands and pinned his arms under her knees, straddling his chest.

Katara squealed when he flexed under her and jerked her up, strong enough to fling her entire body weight off him without momentum as he lifted her off.

"Well, that hardly counts as fair," she said when she found herself balanced, hands and knees supporting her body-weight while he held them up off the ground.

"I warned you that fighting in close quarters will be your undoing. You don't have the strength or the weight to win," he said, smirking at her.

Despite the fact that he was pinned under her, technically, even if she was balanced precariously on his arms, Katara knew who'd won the fight and it wasn't her. When he tipped his arms she lost her balance, toppling back to land on his stomach, straddling him once more. She was panting with the exertion of their battle and Katara leaned back against his thigh when he drew one knee up, also breathing hard.

"You're hurt," he observed, his brow furrowing when he noticed the holes he'd burned in her clothing and the burns upon her skin.

"So are you," she said, nodding toward the bruise forming on his jaw from an ice-ball and the cut on his right biceps from an ice-disk that was bleeding lightly.

Zuko glanced at the wound on his arm before shrugging as though he hadn't noticed it.

"You slapped me with my own hand. Were you just controlling the water, or were you bending through me?"

"Through you. I was too pinned to bend it with my own body," she smiled.

"No glowing this time," he observed.

"No," she agreed. "And no… erm…."

"Chi-gasm?" he smirked when her cheeks flushed pink with embarrassment, unsure how to differentiate to what felt like Bending and what felt like orgasming from their Reiki Kizuna.

"How did you do that?" Meng's voice intruded before Katara could scold Zuko. "That was amazing! I don't know how the two of you can battle like that – like loathed enemies – and just as suddenly turn around and sit together all cute like you'd never even consider hurting one another."

"Control," Zuko smirked, slanting a sly grin at the Earthbender. "It's just a sparring match."

"But you were pinning her and nearly engulfed her in a flame tornado and now you're cuddling," Meng pointed out. "I don't think I could do that? I'd be too annoyed about almost dying."

"It is hard to remember sometimes that I don't have to incapacitate you and fly away on Appa anymore," Katara chuckled, grinning at Zuko.

"I do spend half my time battling you looking around for the Avatar," he admitted.

"You are both injured," Iroh observed quietly, coming closer and eyeing them critically.

"I'll heal it," Katara said. "No use pulling punches when we're training for war, right?"

"Indeed," Iroh nodded. "Though I would prefer it if you didn't kill each other for the sake of practice."

They both nodded their agreement and Katara used her bending to pull some of the surrounding snow over to herself, encasing her hands and using them to heal the cut on Zuko's arm before very carefully reaching for his fac. He watched her closely, tensing slightly at the idea of having his face touched. The bruise was on the opposite side to his scar, but Katara knew he still didn't much like it when anyone touched his face. She smoothed her fingers over the bruise on his jaw, tracing his jawline carefully and feeling the way he moved his hands, resting them lightly on her thighs as she continued to straddle him.

"You've got burns, too," he pointed out when she was finished healing him.

Katara nodded, turning her attention to her own wounds without getting off the Fire Prince. If he minded, he didn't let on.

"Now, back to the lesson," Iroh said, turning away from the two of them to focus on Meng and Kuzon once more. Katara winced, realising they'd interrupted their lesson with their powerful display.

"Still sore?" Zuko asked when the others were sufficiently distracted once more, his hands sliding up her thighs and slipping under the hem of her shirt to press to her lower abdomen.

Katara hummed at the heat of his touch.

"Crazy bending and twisting like that didn't help at all," she admitted, sighing.

Zuko nodded, tracing his fingers over her flesh in a way that made her want to melt into his embrace.

"Get off," he said quietly. "We should make dinner while Uncle finishes his lesson."

Nodding, Katara sighed and got to her feet before offering Zuko a hand up. She was surprised when he took it, letting her pull him to his feet. He slung his arm around her shoulders almost casually as they both headed back inside their temporary dwelling, When she looped her arm around his waist in return he glanced down at her as though startled and Katara blinked, realising with a jolt that he'd subconsciously wrapped his arm around her and tucked her into his side as though he were begging to think she belonged there.

The idea tickled her senses and Katara smiled a little, wondering what to make of all this and what to do about everything. It was one thing to feign romance for the sake of hiding his identity. It was another to have done what they did in the hotel room and hadn't discussed since. It was yet another to be growing so comfortable with one another that standing close was becoming a subconscious habit. When Zuko met her gaze, unsmiling, his eyes searching her face for something, Katara realised something terrible.

She was falling for him. It was more than just sexual tension or mutual attraction or Reiki Kizuna. She was falling for the Prince of the Fire Nation even knowing that all too soon he was going to have to return to the capitol for the sake of regaining his crown and restoring balance to the world. The idea of falling for him, knowing it would all have to end felt a bit like standing on thin ice at the South Pole, knowing that if she stood there long enough, the ice would melt and crack right out from under her feet, plunging her into the icy depths and pain like she'd never known.

She wondered how utterly doomed she must be that even knowing it was going to hurt and going to end, she found herself stretching up on tiptoes and pressing a soft kiss to Zuko's lips, just the same.