A/N: Aaaand here we are, ladies and gentlemen! A new story. This one's been in the works for quite a while, and I admit... it's mainly motivated by the need to write something a little happier for a change.

As some of you may know, I'm a big fan of grim storylines, and some of you have also let me know that this can be a bit much. Well, if it helps, I can get a bit worn down by my own writing style as well. In many ways, some of my earlier stories were fuelled by my need to get certain feelings off my chest, and in some cases, that involved putting some very dark ideas to paper. This time though, after all my medical dramas and other frustrations, I feel the need to put out something cheerier, something brighter, something a little bit more innocent. Yes, there will be a little darkness, but not the unrelenting deluge of misery that I wrote in the past. If anything, I want to write something that might actually seem like an episode of Gravity Falls.

So here we are. Of course, you'll have to be the judge of how well it goes. So, without further ado, my new story: read, review, and above all, enjoy!

Disclaimer: Gravity Falls is not mine. Huge surprise, I know.

Midnight was a special time in Gravity Falls.

As with most things in folklore and myth, it took on its own peculiar reality in that strange little corner of Roadkill County: it was often in the evenings that Gravity Fall's strangest inhabitants left their shadowy dens to explore the town that still squatted obliviously on their doorstep, and it was in the darkest hour of the night that the supernatural truly felt at home on the almost-mundane streets. Steve tiptoed peacefully across the fringes of the forest and swept away unwanted vehicles left offroad. Portal-potties occasionally materialized on street-corners, waiting for unlucky drunks. Scampfires, Kill-Billies and other lesser-known forms of life hunted along the outskirts of town. Gnomes normally hesitant to wander beyond their burrows roamed freely, even sneaking into grocery stores and stealing entire shelves of jam. More than once, sensitive minds had been gripped by terrifying dreams of unearthly beings and Faustian bargains…

And it all began at midnight.

But tonight, the witching hour was even quieter than usual, for Weirdmageddon had come and gone, and both the townsfolk and the supernatural inhabitants of Gravity Falls were still licking their collective wounds. After everything they'd suffered under Bill Cipher's reign, nobody wanted anything more mysterious than their usual routine.

Worse still, the streetlights were still on the fritz following the events of the last few days, plunging the silent streets into coffinlike darkness; in that gloom, even the lights of houses and storefronts seemed curiously muted, as if the shadows were reaching in from the periphery and slowly smothering all illumination.

Perhaps because of this – or maybe just the aftereffects of Weirdmageddon – it seemed that just about everyone in town was fast asleep, even the nocturnal creatures of the supernatural. Insomnia was unknown tonight, and not a single bed remained unslept in: Gravity Falls and all its inhabitants lay in deepest slumber, dreaming pleasantly for a change. Even the Manotaurs were tucked up tight in bed, snoring like erupting volcanoes in the depths of their man-caves.

Nowhere was this truer than the Mystery Shack.

By now, the building was almost fully repaired, and its inhabitants had long since recovered from the events of the Oddpocalypse. Even Grunkle Stan's memory was back in one piece. And after all the effort they'd put into recuperating and helping Stan to remember, none of them were in the mood to stay up: by now, Stan, Ford, Dipper, Mabel and Waddles were fast asleep in their respective beds.

None of them were awake to see the figure slowly creeping towards the Shack.

He was dressed all in grey: from the wide-brimmed Homberg shadowing his face to the imposing longcoat draped over his shoulders, from the scarf that shrouded his mouth to the dull silvery shades that hid his eyes, from the ashen silk tie wrapped around his collar to the leather gloves that encased his spidery hands, everything about him was drab, colourless grey. Every piece of his attire blended seamlessly with the thick, billowing fog that seemed to have followed him up the road… or perhaps he was the fog, for more than once, his body seemed to swirl and flow, even turn transparent. Stranger still was the fact that he didn't walk at all, but instead glided eerily along the pathway, his perfectly-laced shoes dangling almost ten inches off the ground.

Had anyone asked his name, he would have said that he was only a licensed professional.

On past jobs, some had even dubbed him the Grey Professional.

But of course, nobody asked his name tonight; he'd chosen the hour well. Everyone was asleep… and everyone was oblivious.

The Grey Professional hovered to a halt just outside the Mystery Shack and peered curiously through its topmost windows, silently assessing the two figures asleep behind the glass.

Thanks to the dossier he'd procured from the Time Police, he knew everything there was to know about these impressive siblings. Outwitting a Shapeshifter, seizing victory in Globnar, surviving Weirdmageddon, even defeating Bill Cipher himself… yes, Dipper and Mabel had been through a lot this summer. It was astonishing to think of how much they'd accomplished in such a short space of time… and how strange that they didn't appear to be much more than ordinary twelve-year-olds, apart from Dipper's weird birthmark.

Of course, they wouldn't be twelve-year-olds for long. In just two days' time, they were due a birthday.

Lucky number thirteen.

And befitting such a momentous occasion, it was his duty – his job, really – to prepare a very special birthday gift for Dipper and Mabel Pines, something that would make this celebration one that they'd never forget.

Drawing a bulky metal cylinder from the depths of his coat, the Grey Professional began pressing buttons on the keypad built into its side, his long fingers dancing elegantly across the keys as he entered the programming necessary for the creation of a stable wormhole. A moment later, a swirling blue portal began to form in the air above him, much smaller than he was, but more than adequate to the task of delivering this important present to the Pines twins.

And as he watched, something began creeping through the wormhole…

Back in the attic bedroom, Mabel Pines sat bolt upright; absently rubbing a mosquito bite on the back of her neck, she blinked, and tried to figure out what had roused her from sleep. Then, tumbling awkwardly out of bed, she stumbled over to Dipper and shook him awake as best as she could.

"Whaassamatar?" he yawned. "Whaaatimeizzit?"

"Uhhh… ten past midnight."

"Hmrghsdgobaktosleep, Mabel."

"I just need to know, did you hear anything just now? You didn't see any weird lights or anything like that?"

Dipper groaned. "I didn't see or hear anything. Why are you asking me, though? I thought I was the one who was supposed to be looking out for hidden clues and mysteries all the time."

"I don't know. I just… woke up feeling really weird. The old goose over my grave, y'know?"

"Eh, I've had that too. Did you have any weird dreams?"

"No. I don't think so, anyway. What do you think?"

"Possibly something, could be nothing… we'll find out in the morning. You okay to go back to sleep?"

Mabel yawned; now that the initial adrenaline surge had worn off, tiredness was catching up with her again. "I guess so," she mumbled wearily, stumbling back to her bed. "Sorry about waking you up over all this; it sounds really stupid now that I think about it."

"That's okay, Mabel. Sleep well."

"You too, bro-bro. See you in the morning…"

Invisible amidst the fog, the Grey Professional watched the siblings return to bed, barely keeping the smirk off his face as they did so.

Neither of the twins had any idea what had just happened; neither of them had noticed that something was noticeably different… but they would.

This was going to be the best present either of them could have possibly imagined, and it was going to arrive days in advance of the happy date. By the time the party finally rolled around, the Pines Family would be happier than they'd ever been in their entire lives.

And, of course, he'd be rewarded handsomely. Oh yes, most handsomely indeed. The grey man knew that the multiverse offered too many possibilities to plan for the future, but in his line of work, payment was the one certainty to be found amidst the chaos… just as long as he remained true to professional standards.

Once he was certain that everything was in place and ready to begin, the Grey Professional softly turned and hovered away across the horizon, leaving no trace of his arrival except for a few faint wisps of fog. Had anyone been able to hear his voice, they might have heard him softly humming "Happy Birthday" as he disappeared into the gloom – though of course, there was no-one to hear but the gift.

He'd lit the fuse.

Now it was time to watch the fireworks.

It was the knocking at the door that finally woke her.

Maybe it was just because she'd woken up during the night, but Mabel found herself laboriously clawing her way back towards consciousness with all the speed and grace of a drowning swimmer tangled up in a pool cover. It took several minutes to answer the morning questions she normally blitzed through without a second thought (who am I, what is this place, why am I here, what the hell was I doing last night), and when the time came for her to rise from the pillows, she couldn't even find the energy to do much more than open her eyes. Worse still, her head was currently pounding with all the force of a kettle drum being kicked over the edge of a cliff.

After a ten-second delay, two extremely crusty eyelids creaked open, and she immediately cringed in pain as searing white daylight poured in on her. It took a while for her to adjust to the contrast, but once she was well enough to pay more attention to something other than daylight, she happened to glance at her alarm clock, and realized with a jolt of shock that it was almost 9 AM: she'd overslept by two hours.

Last night, she'd made plans to get up early-early and spend the morning on party preparations with Dipper – and after all the adventures they'd failed to share in the days leading up to Weirdmageddon, the two of them desperately needed all the time together they could possibly get. She'd promised to spend time with him on these plans, even promised to wake him up at the crack of dawn… but somehow, she'd managed to sleep through her alarm.

It wasn't just embarrassing, it was an outright failure of her own force of personality: up until now, it was Dipper who suffered from sleepless nights and woke up late, while Mabel had always woken up fresh as a daisy.

In fact, the only thing that made her feel slightly better about the whole thing was the fact that Dipper was even sleepier than she was right now: he was still fast asleep with the covers pulled over his head, refusing to awaken even while someone was knocking at the door.

Oh right, I should probably answer that at some point.

Lurching clumsily out of bed and shambling across the floor like a zombie, Mabel slowly made her way to the door. Once again, though, she barely had the energy to manage this simple task: within five steps, she fell flat on her face, waking up Waddles and prompting immediate concerned snufflings.

Even after she'd hauled herself upright, she only went on stumbling over her belongings or tripping over her own feet. At one point, she somehow ended up nodding off in mid-walk, only to wake up waggling her arm in the general direction of the door handle as if expecting it to open out of pity.

What's wrong with me today? She wondered. Am I sick or something?

She gave herself a little shake, telling herself that everything would be okay once she had a shot of Mabel Juice… but first, she'd have to speak to Grunkle Stan or whoever was knocking at the door. So, finally managing to grab the door handle, she swung the door open wide, and instantly found herself face-to-face with-

Had anyone been standing next to her in that moment, they would have actually heard the long, drawn-out crash of Mabel's train of thought messily derailing. This was not who'd she'd been expecting, to say the least; in fact, for a moment she was certain that the figure standing in the doorway wasn't there at all. This had to be a hallucination, or a dream – or maybe the work of the invisible wizard again.

She blinked rapidly, expecting her visitor to have disappeared when she looked again. But no: there it stood, real as ever.

"Hi there, Mabel!" shouted the apparition.

"Who… who are you?" Mabel demanded.

"Don't you recognize me? I'm Mabel!"

And so she was.

Impossible though it seemed, this stranger had the exact same features as Mabel: the same height, the same build, same exuberant voice, same hip-length brown hair and the same brown eyes lit up by the same excitable stare. She was even wearing the same clothes she liked to wear, though she'd mercifully ignored the shooting star sweater Mabel had been planning to wear today, and had instead settled for a deep blue sweater studded with tiny stars instead.

In fact, the only feature of hers this Other Mabel didn't have was the distinctive smile: true, she smiled as much as the genuine article, but whoever or whatever this stranger really was, she clearly wasn't wearing braces.

Even Waddles seemed to recognize her, and was already excitedly sniffing her shoes and oinking contentedly as the grinning doppelganger patted his ears.

All of this would have been a lot easier to deal with if Mabel had actually been able to point it out, though; unfortunately, all she could say was "B-but I'm Mabel!"

"I know!" said the Other Mabel. "Let's be friends." And with that she flung her arms around Mabel and hugged her tightly.

There was a long pause as the hug dragged on.

"But what are you doing here?" Mabel asked, finally forcing her way free of her double's arms. "How are you here? Did we just start using the old copier again and forgot all about it?"

"I'm not made of paper, silly! Believe me, I'm just as fleshy – and just as IRRESISTABLE-" Here, the Other Mable waved her arms inside the sleeves of her sweater like a runaway windmill, "-As the real thing!"

"Yeah, I can see that. But if you're not from the copier, then where did you come from?"

"I don't know!" said the clone joyously. "Isn't that just great? I woke up a few minutes ago just outside your room and I didn't know how I got here or what I was doing, and the day's only gonna get better from here! Maybe Grunkle Ford can figure it out. For now, it's time we had some serious fun – just you, me and Waddles! The three of us are gonna have ourselves a day on the town! Fashion, art supplies, ice-cream cones and all the friends we can possibly meet! You are going to have a big glass of Mabel Juice and you're going to forget how tired you are, and then get good and hyped for today, because we are gonna have FUN!"

In spite of her confusion, Mabel found herself agreeing with the sentiment: she'd been asleep for far too long anyway, and after all the time they'd spent making repairs to the Mystery Shack and preparing for the party, didn't she deserve a little time off? Besides, wouldn't a clone be the one girl on the planet who knew exactly how to have fun the way she did?

And yet…

"But I don't even know what to call you!" she protested weakly.

"Just call me Mabel2! That's all I am, and that's all I need to be, because today is gonna be all about us! Now… it's time for breakfast! Race you downstairs!"

"Shouldn't we wake Dipper?"

"Nah, why do that? He's tired from all the mysteries; we'll let him sleep for now – it'll be such a nice surprise for him when we get back. Now come on! Last one downstairs has to explain everything to Soos!"

A/N: And there we have it, folks! The first chapter. Feel free to furnish me with your opinions on the story, theories on what you think's going to happen next, and what you make of Mabel's new clone!

This chapter's soundtrack choice is Battle Strategy Conference from Final Fantasy IX.

And now for the code:

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Gsv uvvh ziv kzrw yb nrmwh fmhlfmw
Gsv wlli rh hsfg, gsv kirav rh dlm
Yfg xzm blf tfvhh dszg sv szh wlmv?