Notes: The last day of klarolineauweek involved mixing tropes. So here we have a Harry Potter Mates AU. I hope you enjoy!

Magic Madness

(Prompt: Harry Potter x Mates. Caroline needs Klaus' help with an experimental potion. Rated T. Title from "Blank Space" by Taylor Swift.)

Caroline bends low over the handle of her broom, squinting into the thick tree cover, looking for any sign of civilization. Or at least a reasonable facsimile. Her warming charms are wearing off and she'd stopped being able to feel her fingers a couple of minutes ago so she's willing to settle for even a tiny hint pointing her towards an inhabitant or two. Google had told her that this particular corner of England was barely populated. The terrain would have made settlements difficult and muggles apparently hadn't bothered to try, leery because of some silly urban legends. Caroline was fairly certain that those stories had been bandied about by wizards, that they'd kept the muggles away strategically. The forest she's hovering over naturally contained an abundance of potions ingredients, some of which were reluctant to flourish in greenhouses.

Well, so far. Caroline's a potioneer by trade but she's always excelled at Herbology. She had some theories, ideas to try, and intended to grab some clippings to take with her back home.

Assuming she didn't freeze to death and plummet to the ground, her body never to be found.

Caroline shakes herself, wincing. That had been a little melodramatic, even for her. The setting was clearly getting to her, the nearly full moon and rustling trees were right out of a creepy scene in a horror movie.

She focuses on her task once more, hoping for chimney smoke or evidence of a path. Kol had sworn that his brother had a cottage out here and Caroline needed to speak to him. Kol had warned her that his brother wasn't fond of company and wouldn't roll out the welcome mat. Caroline's determined to find him anyway. Four years of work were at stake, experiments she'd painstakingly researched and executed. She wasn't about to give up now that she'd actually made a breakthrough. She just needed a little help for the next step, that's where Klaus Mikaelson came in. She'd arranged an international portkey and had taken rooms at the closest wizarding village. Going home without even meeting him wasn't an option.

Unfortunately, he's more elusive than she'd anticipated.

Her owls had gone unanswered, the poor birds returning exhausted and bedraggled, her letters still attached. Klaus' floo was set to private and the stone faced English Ministry worker Caroline had tried to sweet talk had been unmoved by her considerable charms, wouldn't bend the rules and help her connect the call.

Kind of a blow to her ego, if she was being honest.

Flying in was her latest plan but it's not going as well as she'd hoped. Nor was she super enthused about what she was going to do next.

If she couldn't find him by air she was going to have to go on foot. Good thing she'd worn comfy boots.

Finding a narrow gap she points her broom down sharply, narrowly dodging branches as she descends. She neatly dismounts, crunching the leaves and twigs that litter the ground. Caroline withdraws her wand from her sleeve whispering, "Lumos," as she spins in a slow circle. The trunks of the trees around her are enormous, bending and twisting together. It's darker on the ground, the moonlight barely filtering through the forest canopy. "Yeah, this is definitely a good place to get serial-killed," she mutters.

Then she hears rustling in the trees.

Caroline whips in the direction the sound is coming from her and braces herself because it's getting louder, closer. It sounds like someone (or something) moving quickly and it's headed straight to her. The light from her wand glints off a pair of eyes and Caroline takes a hurried step back, just before she's knocked to the ground, an enthusiastic ball of muscle and fur licking her face.

She tries to fend the dog off, without much luck, laughing in relief and turning her head away. A shrill whistle has the animal bounding away and Caroline pushes herself up onto her elbows just as a man becomes visible. The dog plants itself at his side, looking up expectantly. The man stops, too far away for her to make out much of his features. He's dressed in dark clothing, shirtsleeves pushed up and a beanie covering his head. "You're trespassing," he clips out, tone unfriendly. "This is my land."

He reaches down to scratch the dog's ears though, leading its tail to thump happily on the ground, so he couldn't be a total ogre.

"Are you Klaus?" she asks. "You brother told me how to find you. Kol?"

"I only have one brother foolish enough to send a guest my way two days before the full moon."

"Actually, the moon is part of the reason why I'm here. I'm Caroline. Caroline Forbes." She waits, hoping he'd maybe recognize her name – her work on werewolf's rights, and her experiments with the Wolfsbane Potion, are cutting edge and she's gotten a little attention.

He doesn't say anything, shows no sign or recognition, and she deflates a little. Maybe he didn't read potions journals out here in the middle of nowhere.

Caroline begins to climb to her feet, nerves beginning to go haywire in the face of his silence. "I met your brother a couple months ago. Kol and my friend Enzo are kind of a thing so he's over at my apartment helping himself to my beer fairly often. We…

He interrupts and Caroline's happy about it. She was beginning to ramble and her plan involved being cool and collected. Scientific.

"Sounds like Kol, love. I fail to see how his lack of manners has led you to my home."

Caroline decides to be direct, "I need your help."

He doesn't move for a long moment and then he lets out an annoyed noise, almost a growl, and stalks forward. "You're a presumptuous little thing, aren't you? First trespassing, now you want a favor?" He leans down and grips her biceps, Caroline gets a flash of his face – stubble and full lips, irritated blue eyes – before she's upright, reaching out to steady herself, her hands landing on the bare skin of his forearms.

At the contact Caroline gets the shock of her life.

Heat fills her and her vision goes white. She sees a flash of herself - wind-tangled hair, nose red and wide eyes - and feels shock that's not her own. Caroline blinks rapidly and stumbles back, ripping her hands off of Klaus.

"Oh my god," she exclaims, a hand flying up to press against her chest. Her heart is pounding and she sucks in the cold night air desperately, trying to get herself under control. "You're my mate?"

"It appears so," he says, the mild words a stark contrast to his shaking hands, still held away from his body. "What did you say your name was again?"

That knocks a little sense into her. He couldn't even remember her name? Rude. "Caroline," she grits out.

He nods. "Right," Klaus says, the word crisp. His face is unreadable and Caroline envies him. She's sure her thoughts, all eleventy-three billion of them, are written all over her face. "Would you like to come in for tea?"

She stares at him for a long moment, unsure if she'd heard correctly. He remains still, watching her expectantly. "Tea?" Caroline finally repeats. "Seriously?"

A faint smile tugs at his lips and he tips his head to the left, "My home is just over there. Heavily warded, it can't be found unless I want it to be. It seems as though we need to have a discussion and I imagine it will be lengthy. We might as well be comfortable."

A lick of a different kind of heat trickles down her spine and Caroline stiffens. Comfortable could mean all sorts of things but now was so not the time to be letting her wolf-y instincts run wild even if she'd just found her mate and he happened to be the kind of hot that was hard to ignore.

He turns, pushing aside a low hanging branch and glancing expectantly over his shoulder, "Are you coming?"

Ugh, there went her dirty mind. Caroline's glad he probably can't tell that she's fighting an ill-timed burst of lust, that the mate bond is too tenuous for him to accurately read her. She has to get a grip. Like, immediately.

Caroline lifts her chin, forcing a cheerful smile. "Lead the way!"


Klaus opens the door, allowing Hannibal to barrel in first. The dog makes a beeline for his bed near the fireplace, giving a great shake before circling and settling down. Klaus takes his wand and mutters a spell to clean up the wet footprints. He motions for Caroline to enter and she does, her curiosity written all over her face. He's careful not to touch her, still reeling from the last time.

Kol is going to be insufferable when he found out that he'd been responsible for setting Klaus' mate directly in his path.

He removes his boots and Caroline does the same, slipping her pack from her shoulders. It hits the floor with a heavy thud and Klaus eyes it suspiciously. Had she been planning on camping? What could be so urgent that she'd do such a thing?

Caroline slips off her jacket and hangs it on the hooks next to the door, turning to him with a smile that reads slightly nervous. "You can sit if you'd like," Klaus tells her, pointing to the battered sofa in the living room. "I'll get the kettle on. Are you hungry?"

"No, thanks." She wanders around the room, stopping to examine the paintings along the wall. Klaus doesn't even realize he's not moved, too engrossed in watching her, until she sits down. The dog immediately approaches, laying his massive head in her lap. Caroline giggles, petting Hannibal as he's demanding. "Aren't you a charmer?" she murmurs. "And so handsome."

Klaus should have known something was off about her. Hannibal wasn't a friendly sort, was more liable to bark and snarl, to scare off anyone who was found on their territory. Yet he'd welcomed Caroline as if she'd come home from a long journey.

The last thing he'd have guessed was that she was his mate. Klaus had never put much stock in the old legends.

When she looks up at him, smiling brightly, Klaus shakes himself and hurries to the kitchen. Tea. He was making tea. He does it the muggle way, needing something to occupy his hands. They're still not entirely steady and he's not sure how well he'd be able to focus his magic for the more precise set of spells required in putting together a tea. He digs into the cupboard for the chocolate biscuits he keeps on hand for Rebekah's weekly visits, sets them out.

But he can only stall for so long.

He carries the tray into the living area and then he returns to the kitchen to drag over one of the two chairs from his rarely used dining table. His cabin is sparsely furnished on purpose. He didn't need one of his siblings (the ones that defied their father and still spoke to him) inviting themselves over for an extended visit.

Caroline's helped herself by the time he gets situated, is swirling one of the biscuits into a cup that looks to be more milk than tea.

Americans.

Klaus pours his own cup, "You said you needed my help?"

"I did," she says slowly, blinking in surprise.

He doesn't blame her. The mate issue was obviously the most pressing topic but Klaus has decided that easing in to that might be best. He hasn't quite wrapped his head around the fact that his life has changed irrevocably and he can't imagine Caroline has processed it either. "With…" he prompts.

She lights up, tucking a strand of hair behind her ear. "My research," she says, with all the pride of a supportive parent. "I was bitten my last year at Ilvermorny. I was on a field trip, my boyfriend and I snuck out of the hotel to get a little quality time in. Teenage hormones, you know? Neither of us paid any attention to the moon. Next thing you know we're running for our lives."

Klaus had been far younger, a year from starting Hogwarts. He'd stormed from the house to get away from Mikael, had returned with his arm shredded. Still, he didn't imagine there was a good time to be turned into a monster loathed by the wizarding world and thought imaginary by the muggles. "I'm sorry," he says. "Was your boyfriend bitten as well?" The thought doesn't sit well with Klaus.

Her smile turns wry, "Nope. He had superior tree climbing skills. Afterwards his family made him dump me. They're kind of a big deal back home, couldn't have their golden child mixing with the likes of me." Her eyes harden, pinning him with a severe look, "I'm a muggleborn. I hope that's not something you have an issue with?"

"I don't," Klaus tells her. Certain members of his family would but Klaus wasn't welcome in their homes either. Caroline was unlikely to ever have to endure their company.

"Good. My parents took the whole werewolf thing pretty well, were pissed about the way I was treated after it happened. I had all sorts of internship offers and most of them evaporated once I was infected. My friend Bonnie's Grams runs an apothecary. She took pity on me and offered me a job. It's a good fit, to be honest. Potions was my favorite subject and I'm good at upselling. The job at the shop also gave me the means to start tweaking The Wolfsbane Potion. And Grams is super generous with the vacation time, didn't even bat an eye when I told her I was going to England and I had no idea when I'd be back."

Her speech tells him several things. Caroline was ambitious, determined, and an optimist and he's now got an inkling of why she'd sought him out. "I haven't used Wolfsbane since Hogwarts. You have to register here to get it, even to buy the ingredients, and I've never wanted to do that. I put up containment wards and turn here."

Understanding dawns and she winces sympathetically, "That must hurt."

The monthly transformations were never pleasant experiences but Klaus had come to find that dwelling on them did little good. "Are you here because of the potion? Your experiments?" He couldn't say he was keen to be a lab rat.

"Yes, but not Wolfsbane. Something I've invented. It prevents the change altogether."

Klaus chokes on the sip of tea he'd just taken, "That's impossible."

She pins him with an arch look, "You're a wizard. Few things are impossible and you know it."

"Forgive me, sweetheart, because I'm sure you're very smart, but it's widely known that Lycanthropy is incurable."

Her nose wrinkles slightly, the only sign of her displeasure at his admittedly patronizing words. "I didn't say I cured it. I'll always be a werewolf. I just eliminated the worst symptom."

Klaus remains skeptical, "And why has no one managed such a feat? It's not like werewolves are a new problem."

"Probably because no one ever really tried," she shoots back, an angry edge to the words. "There's no profit in werewolf research, is there? It took me years. I researched in my every spare moment. I brewed my first batch four years ago and it was a miserable failure. I turned blue and itched for a week. I've tried a new variation every month for the last 4 years and 3 months. I finally have one that works."

"You're saying you didn't change last month." He does his best to sound neutral but he's honestly floored.

"Nope," she chirps. "And I was laughed out of the American Ministry when I tried to set up a meeting to discuss my findings. I had hoped that they'd be willing to help me manufacture it on a larger scale but they said my trials were insufficient. Wouldn't even read the file I compiled. And I don't actually know any other werewolves so…"

"So you came to me."

"I didn't expect…" she gestures helplessly between them, face twisting apologetically.

"For me to be your mate."

"Yeah."

Her eyes are downcast and Klaus doesn't like the slump of her shoulders. He nudges her foot with his and she looks up. "It's all right, sweetheart. I can't say I expected to find you when I woke up today either." She cracks a brilliant smile and Klaus has a fleeting wished that he'd taken a seat closer to her. He shifts on his hard wooden chair, reaching for the pot of tea to top up his cup.

"I never put much stock in the stories about mates. I read everything I could get my hands on right after it happened, I couldn't stand the way everyone was looking at me. All the pity and the fear. Most of my friends suddenly got super busy so I had a lot of free time. There were a couple of old journals that talked about mating but they just didn't seem credible. One touch, an instant connection growing into fierce devotion." She flushes prettily, staring intently on her cup and Klaus can easily guess where her thoughts had gone. "Who would believe that?"

He'd read the same journals. The woman who'd written them had married her mate. Her story spanned decades and she'd often written effusively about the intense physical connection she'd felt, how quick desire was to kindle, how hot it burned between a mated pair.

His thoughts had always been similar to Caroline's, finding the idea of a mate overly romantic. He had dismissed the journal as wishful thinking. Now, watching Caroline sneak a glance at him, the pink of her cheeks growing even deeper, he can't say he'll mind if he's wrong.

She's lovely and bright and he's eager to touch her.

A quiet falls over them, not as awkward as it should be considering they're near strangers. "When do I need to take the potion?" Klaus asks.

She beams at him, "So you'll try it?"

"You have, so it's not as if it'll kill me." He's not overly thrilled with the idea of her dosing herself with experimental potions but there's nothing he can do about it now. Klaus also suspects that Caroline would bristle in indignation should he voice his thoughts aloud.

"It has to be in your system when the sun sets. I have the precise time written down so we'll take it about a half hour before."

Klaus doesn't comment on the fact that she's intending to take it with him though a thrill of pleasure unfurls at the news. "Are there any side effects I should know about?"

"I had the chills for about ten minutes. Was crazy thirsty for an hour."

Those were certainly manageable. Far better than turning blue and itching. "So we'll apply some warming charms, build up the fire. Have water on hand."

She looks thrilled, practically vibrating in her seat. "Klaus, thank you. Thank you so much." Caroline stands and Hannibal makes an annoyed sound at having been dislodged. "I have a room at an Inn in town but I'll apparate back tomorrow with all my research and we can go over the details then."

"I want you to stay," Klaus blurts out, pressing his fist to his mouth as soon as the words are out. He rarely has the opportunity to be impulsive, isolated as he is, but it seems as though he still has a knack for it.

She'd stilled when he'd spoken and she doesn't seem offended. Klaus takes that as a good sign. "We can transfigure the couch," he offers, deliberately light. "You can sleep in the bed. I have plenty of blankets. "We'll go to town tomorrow to pick up your things, plus anything else you might need."

"This is crazy," she says but it sounds like she's trying to convince herself.

"Don't think about it. Do you want to stay?"

She inhales sharply, a smile growing as she nods, "Yes."

"Then stay," Klaus says simply.

They'll figure out the rest later.