a/n: so this chapter reveals a few things, and I'm so nervous for you guys to read it and I don't know why. (like literal butterflies in my stomach right now, what is wrong with me?) hope you enjoy and thank you so much for reading! a review would mean the world to me :)

It's still pitch black in the tent when Killian blearily opens his heavy eyes just a crack, he can only make out a few ambiguous shadows in the darkness before exhaustion has his eyes falling shut again. He's groggy and tired, and the thoughts in his brain are a little muddled as he tries to piece together what has him waking up in the middle of the night.

It's only when he shivers that he realizes that the culprit for his lack of sleep is the freezing temperature. Groaning, he pulls his blankets tighter around him and then blindly reaches his arm out in search of Emma—body heat, after all, is the most enjoyable way of generating warmth.

But the only thing his hand finds as he reaches for her, is empty air and tangled blankets. Confused, he drags his eyes open again and continues to pat at the ground beside him as if somehow he'll find her in the inches of the bed he hasn't checked. And as the growing panic inside him scatters all remaining traces of sleepiness and his eyes adjust to the darkness, he sees exactly what he was dreading to find, his heart plummeting to rest somewhere near his stomach as he scans the empty tent.

Emma's gone.

Jolting upright, Killian's heart hammers as he throws the blankets off the bed, a futile last attempt to convince himself he's dreaming, to convince himself that she's still here and sleeping soundly next to him.

But she's not, and fear squeezes the breath from his lungs.

He knows exactly where she's gone—and damn it Emma, he'd asked her not to do this. At the very least he'd asked her not to do this without him.

Scrambling from their bed, he gropes around in the darkness for his shoes, cursing everything between heaven and hell when he can't find them. He only makes more of a mess as he throws things about the room in his frantic search. He's not sure how long Emma has been gone, but he's scared that he's already too far behind, scared that he won't be able to find her. And every second he wastes is a second he can't afford to lose.

Finally finding his shoes buried beneath a blanket he more than likely tossed on top of it, Killian wrenches them on and then grabs his jacket, rushing out of the tent before he even starts to yank it on.

But in spite of the urgent desperation in which he scrambled to get out of the tent, he pulls to a complete stop once outside. Scanning the perimeter of the campsite, Killian clenches his jaw in frustration. It's completely encircled by trees, and he has no way of knowing for sure which direction Emma went.

Sucking in a sharp breath through his nose, his eyes continue to dart across the forest's edge as he wrestles with the decision on where to go. It's not until his gaze falls on the area where they first entered the forest that Killian releases his held breath in an audible gust of air.

Emma wanted to go back into the forest, and something inside him just knows that starting where they came from is what she would do. And even if it's not, it's the only lead he has and he can't afford to waste any more time.

Praying that he's right, he pulls the collar of his jacket up to protect his neck from the cold air and jogs towards the edge of the campsite—the sounds of his footprints crunching against the half frozen ground the only sound penetrating the quiet night.

As he enters the forest he immediately begins searching for some sign that Emma was here. He's grateful that the moon is almost full, as it lends him just enough light to make out his surroundings even with the cover of the trees above him.

He would never boast of having any semblance of tracking skills, his expertise lies with the waves and rhythm of the open sea, not with the dense and smothering confines of the forest. But he's spent enough time surrounded by this planet's environment to pick out when something has disturbed it.

Freshly broken branches and slender footprints are his first clue that he's going in the right direction, and it's like a heavy anchor is lifted from his chest. He has hope of catching up with her, of finding her before she finds whatever the planet has in store for her.

He runs as much as he can, ignoring the burning in his lungs as he pushes himself forward. More than once he has to backtrack when he loses sight of her tracks, and each time he does so, he curses his lack of attention and forces himself to run harder to make up for the lost time.

The trees loom dark and tall above him, a daunting presence that mimics the darkness of his thoughts. He doesn't know where the magic is leading Emma, but he just knows that what's waiting for her when she gets there is nothing good. And as much as he wants to shield her from whatever it is, a helpless feeling has started to bubble in his chest ever since Emma started feeling the magic again. It's like every cell inside him is on edge, as he battles with the feeling that whatever is about to happen is inevitable, as much as he doesn't want it to be.

But no matter what, he will keep her safe—even if that means diving headfirst into danger with her.

It feels like an eternity later when he finally sees her silhouette off in the distance. He's too out of breath to call out to her so he just keeps racing towards her. He can pick out the exact second that she hears him—her body stiffens and she stops walking, and he can almost see the intensity in which she's listening to the forest around her.

He's almost to her when she whips around faster than a beat of his racing heart, her hands raised in defense and already starting to glow with the magic she's summoning. Killian skids to a halt, breathing hard, and watches the recognition dawn on her face.

She drops her hands and straightens her spine. "Killian?"

He forgets in that moment that he's upset with her, forgets that the last half hour of his life has been nothing but the same fear that gripped him the second he realized she'd left. Forgets everything except the desperate and visceral need he has to feel her in his arms.

He sprints the last few steps to her and pulls her to his chest as though being apart from her for even a second longer is an anguish he can no longer endure.

She wraps her arms around his neck and he crushes her tighter to him, entwining one hand in her hair and burying his face in her neck as he takes a deep breath. The relief that spreads through him is instant, a wave of cool water that courses through his veins and soothes the panic that had settled inside him.

He made it in time. He found her.

"What are you doing here?" Her question is a muffled sound, caught in the fabric of his shirt, but it grounds Killian in the reality of why he had to follow her out here in the first place.

"What am I doing here?" he asks incredulous as he pulls away from her just enough to look her in the eye. "Bloody hell, Swan."

She gives him a sheepish look before dropping her lashes and staring at the forest floor. Taking another deep breath Killian steps away from her and drags a hand down his face.

"Why?" he asks her. He's trying to understand her headspace, but a part of him is having a hard time even fathoming why she left after he begged her not to.

"It wasn't stopping, Killian." She looks up at him and gives him a painful smile as an apology, but there's a fiery defensiveness in her eyes at the same time. "I couldn't sleep. It was starting to get painful. And I know you don't trust it—trust me I know—and your reasons are valid, but Killian, I need to know what this is about."

Throwing his hands in the air he groans in frustration. "You should've told me it was getting worse. I promised we would figure it out together."

"I know," she counters, folding her arms and standing firm. "I was worried you wouldn't let me leave."

There's a moment where nothing exchanges between them except a tense stare. Determination shines bright and fierce in her eyes, and he knows she's going to follow this thing with our without him—there's no use fighting her on it. So with a sigh, he steps back into her space and grabs one of her hands with a tender gentleness. He's upset and more than a little frustrated, but it stems from a concern for her safety and that, above all else, is what he wants her to know.

She hesitates, looking at their hands for a few lingering seconds before she softens and threads her fingers through his, giving his hand a gentle squeeze.

"I wouldn't have liked it, but I never wanted you to go chasing this on your own. You should've wakened me."

"I know," she repeats. "I am sorry I worried you."

"That's an understatement if I ever heard one, love." He drops his forehead to hers and closes his eyes before asking a question he's already dreading the answer to. "How bad is it?"

She sighs. "The humming hasn't stopped since I decided to leave the campsite. And it's…it's leading me again."

He straightens in one sharp movement, furrowing his brow in concern. "You mean it's hurting you again." And it's not a question, because he knows there's only one possible way it can lead her—and he expected this to happen, but a part of him still hoped it wouldn't. If the planet's so bloody magical, then why can't it find some other means to lead her? He's pretty sure a magic glowing trail would accomplish the same thing, and he'd be more inclined to trust it if it wasn't torturing her.

Emma shrugs as though her pain and suffering is of little consequence and Killian can't help but grit his teeth. He really hates this.

"I'll be okay. But there's really only one way to get it over with," Emma says, tilting her head towards the dark expanse of trees in front of them. "Shall we?"

-CS-

Breathing heavy, Emma straightens her spine and shakes off the last echoes of pain still lingering from the most recent attack.

"That one lasted longer," Killian sighs as he continues to rub a hand up and down her back. "Are you okay?"

She nods and lets herself fall into his chest, savoring the feel of his arm wrapping around her as he presses his lips to her hair.

He's asked her that same question after every single burst of pain, and she can tell by the way his entire being seems to be saturated in never ending concern, that he's suffering his own type of agony as he watches her endure every painful assault on her senses.

She closes her eyes and shifts a little in his embrace only for her legs give out a little beneath her. Killian tightens his hold, supporting her weight, and if it weren't for his arms around her, she's not sure she'd be able to hold herself upright at the moment.

She's exhausted.

And thinking back on it, choosing the middle of the night to follow the planet's humming probably wasn't the best choice. She hasn't slept since the night before, and light has been slowly sneaking into the sky for the last hour or so, meaning they've spent the entire night out in the forest.

Not to mention the physical toll this is taking on her. Each time she steps in the wrong direction and the familiar pain surges through her body, she feels like her limbs are that much heavier with fatigue.

Hiding her face in the space between his neck and shoulder, she takes a deep breath and lets the smell of his skin comfort her.

"Do you want to rest?" Killian whispers against her hair. "Sleep for a little while and regain some of your strength?"

Shaking her head Emma straightens out and looks up at him. "No, let's keep going for a little longer. Maybe we're getting close." She's tired but she doesn't want to stop. Not yet at least.

"Swan—"

"I'll be fine for a little longer. But if we don't get there soon I'll take a break I promise."

Killian lets out a heavy breath and tips his head back to look up at the heavens. "Is there any use arguing with you?"

"Probably not." She says softly, reaching up to place a hand against his cheek. He looks back down at her then, and in the blue of his eyes she sees a torrent of anxiety and unease.

Tracing her thumb along his cheekbone, she pulls his head down and rests her forehead against his with gentleness. "I just want to go a little farther—but I promise I'll rest soon."

Killian remains silent, but he keeps his forehead pressed to hers and closes his eyes. She knows he's biting back whatever it is he wants to say, knows he wishes she hadn't chased after this thing. And she swears he's going to grind his teeth to dust with the way he keeps clenching his jaw, but they're so close—she can feel it.

Pulling away from him Emma reaches for his hand and gives him a small smile that he returns only half-heartedly.

"Only a little farther," she promises again as she rubs her thumb back and forth across the back of his hand.

Steeling herself for her next step she takes a deep breath and closes her eyes as she places her foot down in a new direction. As soon as the sole of her boot touches the forest ground she feels Killian tense beside her as they wait to see what this step will cost them. Thankfully it comes pain free, and they both deflate with relief and continue forward on their newest path.

Emma knows they're nearly there by the way the humming picks up in both speed and vibrancy. It pounds and roars throughout her entire body, a song that rings through her veins and obliterates every other sensation.

She's never felt it this strong before—not even when it led her through the forest for the first time only days ago.

And as the force of it surrounds her on every side she finds herself wondering if maybe Killian's been right this whole time—that it's something dangerous and not to be messed with. Because what she feels now is not some meek and calm buzzing, but a force filled with unmistakable raw power and it's the first time it really dawns on her how dangerous the consequences of following after it could be.

But it's too late to turn back—she's tumbling towards it no matter what she does.

A sudden hesitancy to continue forward surges through her and she begins to slow down, almost pulling to a complete stop. She knows there's no way out of this now, that with the magic sending crippling pain through her with every wrong step she has no choice but to see this through.

But despite the inescapability of it she can't help but want to prolong the inevitable, so she slows down her steps just the same.

"Emma…"

She looks up at Killian expecting him to ask her why she's slowing down, only to find his brow furrowed in a confusion she can't help but think is completely unrelated to the pace of her walking.

"What is it?" her voice is strained and she feels the beginnings of nerves fluttering wildly inside her stomach. The sudden intensifying of the humming coupled with Killian's strange behavior causes her heart to race with anxiety.

"I…I feel it." Killian looks at her, his mouth gaped open in shock.

Emma's eyes widen, and she swallows. She's sure she heard him right but she's not quite sure what to make of it. "You feel it?"

"Aye. The humming…I can feel it." He looks around him as if he'll suddenly be able to see it too. "On my skin—right here," he gestures to his arms as if she doesn't know what it feels like, as if she hasn't felt the sensation a thousand different times. "What do you think this means?"

She shakes her head, completely baffled. "I don't know. It feels stronger here—maybe it's strong enough for you to feel it now?"

It's the only plausible answer she can think of. And if Killian, who doesn't have magic, can feel it, they must be close. And she's not as excited about it as she thought she'd be.

"Bloody hell," he whispers. "What is this thing?"

"I don't have any idea," she says shaking her head again. And part of her wishes they were back in their tent, sleeping away the early hours of the morning, wishes that she hadn't dragged them into chasing this thing.

Licking her lips she looks off into the distance and then back at Killian before expressing her fears. "Killian what if you're right? What if this thing is dangerous? What if something happens to you? We've survived so much, and what if my stupidity is what finally—"

"Hey, hey, hey," Killian interrupts, grabbing her shoulders and ducking his head to look into her eyes. Emma takes a shuddering breath as he rubs his hands up and down her arms. "Swan, I'm not denying that you are without a doubt one of the most stubborn women I know. And heaven knows I wish you would've just waited until we talked about this rationally before you went chasing after it in the middle of the night. But whatever this is—I swear to you I won't let anything happen to you."

Emma's eyes dart back and forth between his eyes as she takes in what he says and tries to let his words calm her. But with the way the humming is consuming her senses she can't help but feel like she's choking on the disarray of unease and regret inside her.

"I'm sorry," she murmurs, "I'm sorry I got us into this mess."

Killian smiles at her softly and lifts his hand to tuck her hair behind her ear. His fingers skim down the side of her neck and her skin tingles from his touch long after he drops his hand.

And it's amazing, the way something as simple as his touch can drown out the overpowering sensation of the planet's humming, but it does, even if just for a moment. And she's convinced that the feel of his skin against hers is a certain type of magic all its own.

"We're here now, love. And I'm with you. Whatever happens we'll face it together."

Emma swallows and nods keeping her eyes locked with his for a few more lingering seconds, finding strength in the warmth of his gaze before she grabs his hand and continues walking.

As they walk they remain silent, but the air around them is anything but peaceful or quiet. Killian seems even tenser now that he can feel the humming and Emma can think of little else except what they might possibly be walking into.

It's a little while later when, off in the distance, she can make out a wall of solid rock ahead of them. It's a cliff side of some sort and she can see that amongst the various cracks and crevices is nestled a significant gap in the rocks surface.

And this is exactly what she doesn't need—for the humming to take them to a dark and ominous cave where they won't be able to see what's waiting for them. But the longer they walk without another attack, the surer she is that this cave is exactly where it's taking her.

Killian squeezes her hand when they make it to the opening, giving her a meaningful look before he steps in front of her and leads her inside. And though her heart melts a little that he wants to act as a shield between her and whatever is inside, she wishes he would let her go first for the exact same reason, the last thing she wants is for Killian to get hurt because of her.

Their first steps inside the cavern are in some sort of narrow nature-made hallway, and it's not as dark as she expected it to be. In fact, at the end of the tunnel the resonances of some source of light shimmers and pulses, beckoning them forward.

With cautious steps, they continue towards the light only to find that the tunnel curves to the left and opens up to a much larger room.

Emma gasps as she takes in what's in the chamber in front of them. A column of light, pulses and snaps with visible energy in what she can only explain as a rift where the literal space it occupies has been torn apart to accommodate it.

Mesmerized, she drops Killian's hand and steps towards the blinding light like a helpless moth that's drawn towards the flames of a fire.

"Do you feel that?" she asks breathless. The air around them his humming with such intensity that she knows without a doubt that the source of it is emanating from the light in front of them. This is it—the source of the planet's magic that she's connected to so many times. The source of the magic that helped her heal Killian, that led them to Elsa and Ruby.

She immediately finds herself retracting her most recent fears. There's no way that something this bright, this stunning, is a danger to them.

Without even thinking about it she raises her hand, inching forward as she seeks to touch it, to see what the light will feel like as it runs through the space between her fingers.

"Hold on a moment, Swan."

Killian's hand is suddenly around hers, stopping her. His voice snaps her from her reverie and she jumps a little before turning to look at him.

The line of his jaw is tense and his brows are knitted together in clear worry and apprehension. "Don't touch it. We don't know what it could do to you."

Emma opens her mouth to respond when an unfamiliar voice slithers to them from the edge of the cavern.

"I'd listen to the sailor, dearie."

Turning sharply towards the direction of the voice, Emma spots the one man her parents had hoped she'd never come across, the reason for her countless stays aboard The Swan.

There leaning against the cave wall, arms and ankles crossed like he doesn't have a care in the world, a wild and sinister smirk contorting his lips, is the Dark One.