A/N: So, this is going to be a little bit different from what I usually write. ;) This story is a birthday request for my sister. She wanted me to write a Gravity Falls fanfic for her, and this was the idea I came up with.

Timing/Spoiler Warnings: this story takes place during season one of Gravity Falls, i.e. before they find out who the author is. On the DGM side, this takes place in a semi-AU where some time has passed after the end of Hallow. For this story to make the most sense you will have to have seen at least a couple episodes of Gravity Falls and the entirety of DGM, however, all you really need is a basic familiarity with the characters in each story. I tried to keep it as spoiler free as I could.

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Gravity Falls, Oregon. The weirdest place on Earth. The site of UFO crashes, haunted mini marts, video games that come to life, and the summer home of Dipper and Mabel Pines.

The brown haired twins were currently out wandering the woods, after being tossed out of the Mystery Shack for annoying Grunkle Stan. Dipper was engrossed in The Journal, looking for signs of the next new and strange creature they would come across. His sister Mabel was only half listening to his ramblings, humming to herself and picking wildflowers.

A metallic screeching up ahead caught their attention, and they ran excitedly towards the sound, only to leap back among the trees at the sight of the metal monster that occupied the clearing. It looked almost like a medieval knight, though its armor was a sleek and shiny red. Laughing over their initial fear, they made their way out into the clearing, Dipper calling out to the giant robot. "Nice one, McGucket! You almost got us this time! What's it supposed to be anyway?"

Expecting the bearded kook to pop out from the robot's midsection, the twins were taken completely aback when the large machine turned around and pointed its sword at them. "Ah, at last! Human children! I think I'll have some fun with you before I kill you!"

Mabel laughed at what she thought was one of the old man's games. "Yeah right, McGucket. Like you could ever-"

Her words turned into a screech as the mysterious robot swung its sword at her, only missing because Dipper had pulled her away. "Uh, Mabel, I don't think this is one of Old Man McGucket's..."

As if agreeing with him, the robot swung his sword at the twins once more. They turned around and ran as quickly as they could back into the woods, screaming the whole time. They could hear the machine tromping along behind them, chopping down the trees and branches that got in its way. They had the advantage of size among the densely packed trunks, but the metal monster was stronger and faster than they were and was gaining on them.

Dipper suddenly skidded to a halt, kicking up dirt, as something strange appeared right in front of him. The unexpected stop caused Mabel to crash into him, and the two fell to the ground. She opened her mouth to yell at her brother, but the words died in her throat when she saw what had made him stop running. "What's that?"

Blocking their path was a giant clock face. Its oddly shaped hands were spinning in a way that a normal clock's wouldn't. It was glowing green and semi-transparent, allowing them to see through to the woods beyond it. Only those weren't the Gravity Falls Woods, they were darker and infinitely creepier.

"I don't know, Mabel. It looks like some sort of-" Dipper's speculation cut off as a dark shadow fell over the twins, and they turned from the mysterious clock to find that the giant robot knight had caught up to them. They huddled closer together and squeezed their eyes shut as the machine brought his sword down on them. But instead of getting sliced to pieces, they heard the clang of metal on metal, and they cautiously looked up.

Standing between them and the giant robot was a tall Asian teenager. He was dressed all in black with a long coat that swirled around him and he wore his long navy hair pulled up into a high ponytail. He had a katana raised above his head, blocking the robot's sword from coming any further.

Before the Pines twins could wonder who he was or where he came from, two more teenagers stepped from the clock, which the twins now knew was some type of portal. The newcomers were both dressed similarly to the first teen; from the silver symbols on their jackets it was obviously a uniform of some kind. The taller of the two newcomers wore an eyepatch over his right eye and had a bandana in his flaming red hair, and the smaller one had short snow white hair and was wearing a gear in front of his left eye, which was red and had a strange scar running through it.

Taking in the scene, the redhead spoke as he stepped fully into the woods. "Nice block, Yuu!"

Kanda growled as he deftly pushed the level three akuma away and turned his blade on Lavi. "What have I told you about using my first name, Baka Usagi?"

Lavi yelped and moved to hide behind Allen, but the white haired teen had launched himself at the akuma, drawing his own sword just in time to chop off the akuma's sword arm before it went after the kids again. Seeing this, Lavi drew his own weapon, and the three exorcists had the akuma finished off before it could even think of a single way to taunt them.

Kanda immediately went back to chasing the rabbit, leaving Allen to deal with the two kids by himself. They were clearly twins, having the same wavy brown hair and being roughly the same height. He approached them cautiously, trying not to scare them. "Are you two ok? You didn't get hurt, did you?"

Dipper and Mabel had picked themselves up and were staring wide eyed at the white haired teen as he turned his sword back into his left arm. That was almost as weird as the giant robot exploding into dust when it was defeated. Dipper found his voice first, though it quickly turned into babbling. "Wow! That was awesome! What you did with your sword-! And the other guy-! And that fire dragon-!"

Mabel smacked her brother to make him shut up, and smiled at the white haired teen. "Thanks for saving us. I'm Mabel, and this is my brother, Dipper."

She offered him her hand and he shook it. "Nice to meet you, Mabel. I'm Allen. The redhead is Lavi, and the one chasing him is Kanda."

Dipper bounced excitedly beside his sister. "So what was that thing? And why was it chasing us? And how'd you turn your arm into a sword?"

His next question was cut off when Allen suddenly turned and shouted at his companions. "Incoming!"

Lavi and Kanda stopped fighting and readied their weapons. Seconds later, there was a deep rumble and the sky filled with level one akuma.

Dipper and Mabel gaped at the giant metal creatures that had appeared out of nowhere. The weird balloon-like things had disturbing clown faces, and lots and lots of guns. Then everything went white as they were wrapped in some sort of soft fabric that appeared out of nowhere. They could hear the fighting between the three teenagers and the weird creatures, but somehow knew that they were safest staying where they were.

The huge number of level ones was no match for the three exorcists, even with Allen dividing his focus between fighting and protecting the twins with Crowned Clown's cloak. In no time at all, the akuma were all wiped out.

The teens deactivated their Innocence weapons, and looked down at Dipper and Mabel, who were bouncing up and down and rattling off questions so fast that the teens couldn't make out any of their words. None of the exorcists really wanted to explain things to the pair, but it was obvious from the looks on their faces that they wouldn't take no for an answer. With a sigh, Allen answered the first question he could make out. "Those creatures are called akuma. They're-"

He was cut off by an excited shout from Dipper as he pulled out The Journal and began flipping through it. "Akuma... akuma... dang! I don't see it! It's not in here!"

Lavi looked over his shoulder curiously. "Whatcha got there?"

Dipper tried to pull The Journal away, feeling slightly threatened by the older boy invading his space, but the redhead managed to pull the book from his grasp. He adjusted his hat and reluctantly explained. "It's a book on all the mysterious creatures that live around these woods."

"That's awesome!" Lavi's one green eye sparkled as he began to read through the pages; his Bookman spirit jumped at the chance to learn something new. "But you won't find akuma in this book. They're not from here."

The teen's easygoing manner put Dipper at ease, the boy recognizing Lavi as a fellow mystery enthusiast. "Then how did they get here? And where did they come from?"

Impressed with the kid's inquisitive mind, Lavi told him the whole story. "Our friend Miranda has a weapon that controls time. It recently evolved, and when it did, she momentarily lost control over it. It opened a portal from our time into yours, and the akuma got sucked into it. We followed so that we could defeat them before they did any damage over here."

While Lavi and Dipper chatted, Kanda scoffed and leaned against a tree. He was ready for this nonsense to be over so that he could go home. Feeling someone watching him, he looked down to see Mabel staring up at him with stars in her eyes. "Che. What do you want, brat?"

The brunette girl fiddled with the hem of her watermelon sweater in a way she hoped made her appear older and more mature. The navy haired teen was incredibly hot, and he had that brooding nature that made him even hotter in Mabel's eyes. She giggled as she looked up at him. He just scowled at her. "Well? Get on with it!"

"Your hair is so long. It's very pret- er, handsome." She rocked back and forth on her heels and continued to fiddle with her sweater. "Would you maybe want to go to a movie with me tonight?"

Not knowing or caring what a movie was, Kanda scoffed at the little girl's attempt to flirt with him. "Why would I want to do that, brat?"

Weirded out by the way his companions were interacting with the kids, Allen decided it was best to just finish their mission and quickly go back home. He activated his cursed eye and began searching out the rest of the akuma. Locating them, he turned to the others and addressed them, not caring if he was interrupting anything. "I've found the rest of the akuma. There are about a dozen left. You guys coming or not?"

Without waiting for a response, he turned and walked into the woods, using his eye to guide him. He would have preferred to leave the kids behind, but it was clear from everything else that had happened that they were going to follow along anyway, and he knew that it would be easier in the long run to just let them come.

While they walked, Lavi and Dipper talked nonstop. They discussed The Journal, the mysterious happenings in Gravity Falls, and the redhead gave Dipper his insights on the Author. Lavi even explained everything about the akuma and Innocence to the inquisitive boy.

Mabel didn't care where they were headed; all she cared about was getting closer to the mysterious teenager called Kanda. Every annoyed scowl that he shot her way only fueled her crush, and she practically drooled over him as she followed along behind him.

Trying his best to ignore the smitten girl, Kanda focused his annoyance on Allen. "You better not be getting us lost, Moyashi."

Allen huffed as he hopped over a fallen log. "My name is Allen, Bakanda! And I know exactly where we're going. In case your pea sized brain has forgotten, I can see the souls of the akuma."

"Che. I was referring to getting back to the portal, moron." The pair continued to bicker back and forth, the occasional curse word from the samurai only serving to make Mabel more smitten with his bad boy attitude.

After about an hour of hiking through the woods, Allen finally came to a stop. The others noticed and stopped as well, but Mabel wasn't paying attention and crashed into Kanda. She giggled nervously as the samurai turned and glared death at her. "Oops. Sorry."

Ignoring them, Allen spoke without turning around. "They're just up ahead. I count eleven level twos, and two level threes. Dipper and Mabel, you two need to stay here."

With that, he was gone, running ahead with Kanda at his heels. Lavi gave The Journal back to Dipper, and then he too was running off. Alone in the little clearing, the twins stared after the teens. Then, with a conspiratorial glance at each other, brother and sister began to silently follow them.

They made sure to go calmly, staying far enough away that the exorcists wouldn't notice them. And when the teens drew their weapons and burst into a clearing, Dipper and Mabel stopped where they were still hidden by the trees.

The twins watched in awe as the three teenagers fought the akuma that were in the clearing. Lavi was wielding a hammer that was twice the size of his body as if it weighed nothing. Kanda was unstoppable, slicing through everything in his path with his katana, which was now glowing and somehow split into two swords. Allen was fighting with his left-arm-turned-sword, and while Kanda had better sword skills, the white haired teen was definitely the stronger of the two. Despite the exorcists being outnumbered four to one, they had the advantage, and the akuma were quickly defeated.

As soon as it was safe, the twins ran out into the clearing. Mabel wrapped Kanda in a hug, her arms tight around his waist. She looked up at him with sparkles in her eyes and began babbling about how gorgeous he was when he fought. Dipper wasn't much more composed than his sister, rattling off question after question.

Kanda cursed and tried to peel Mabel off of him, but she wouldn't let go. He tried to use Mugen on her, but was stopped by the Moyashi. Allen shoved the katana away and crouched down so that he was at Mabel's eye level. He smiled that brilliant smile of his that could charm absolutely anyone. "Hey, Mabel? Kanda's an idiot. He's not worth your time."

Normally Kanda would have protested being called an idiot by the idiot Moyashi, but the white haired teen's words and actions actually snapped the little girl out of her boy crazy mode, so he could let it go this one time.

Mabel echoed Allen's bright smile as she returned to her usual, bubbly self. She laughed sheepishly and put some distance between her and Kanda, who she now realized looked like he wanted to murder her. "Heh, guess I got a little carried away."

Allen laughed. "Don't worry about it. He has that effect on everyone."

His next words cut off when Mabel reached out and began tracing the pentagram of his scar with her finger. She gave him a bright smile as she giggled. "There's a star on your forehead. That is so awesome!"

Just as Allen was about to laugh along with her, there was a rumbling in the woods nearby. All five young people looked up just in time to see what looked like a brown bear with multiple heads and arms get chased into the clearing by a group of creatures that were half bull and half muscular, bearded men.

The arrival of such strange creatures put the exorcists on edge. Lavi and Kanda's hands strayed to their weapons as they looked to Allen, but the white haired teen merely shrugged at their unspoken question. "They're not akuma."

The words made the creatures stop in their tracks as they noticed that there were humans present. The manotaurs began whispering conspiratorially among themselves, forgetting all about their quarrel with the multibear. Immediately recognizing Dipper, the multibear quickly scampered over to where the boy was standing with Lavi, seeking the security that having other people around provided.

Dipper smiled at his friend as he hid, but his inquiry into what had happened was drowned out by raucous laughter from the manotaurs. The tallest of the manotaurs, a red haired beast by the name of Chutzpar, stepped forward and began hurling insults at the group of humans.

The comments of 'weak' and 'puny' were ignored, as the humans knew they were just trying to pick a fight. Lavi and Dipper focused on the multibear, the redhead intrigued by the creature and Dipper worried for his friend. The others laughed amongst each other at how dorky their friends were, but the moment ended when Chutzpar said something that he really shouldn't have. "Is that a guy or a flat-chested girl? With hair that long, it's hard to tell."

Kanda, who was still thoroughly pissed over the whole Mabel thing, immediately rounded on the lead manotaur over the insult. "What did you just say?"

Knowing from experience exactly what Kanda was capable of when he was insulted like that, Allen tried to intervene. "Don't. Don't say it again."

The white haired teen's warning went unheeded, and Chutzpar laughed tauntingly and repeated the insult. "You heard me. With hair like that, there's no way you're a real man."

Kanda drew his sword, activating it in a flash and launching his first illusion at the manotaurs, who let out very unmanly screams and ran from the ghostly insects. But they quickly collected themselves, pulling out clubs and other weapons and rounding on the samurai, who had no trouble keeping up with them despite the fact that he was outnumbered.

Allen gave up on trying to stop the fight with a heavy sigh. He sat down beside Mabel, who had pulled out a bag of popcorn and was laughing at the spectacle her brother was making of himself. The white haired teen couldn't help laughing along with her at the sight, and gratefully took the popcorn she offered him.

The multibear had pulled out his tape player, and he and Dipper were singing along, loudly and off-key, to Icelandic pop sensation BABBA's hit song "Disco Girl". Lavi clearly didn't know the words, but he was dancing along with them, having fun and not caring that the looked completely ridiculous.

A loud boom and something dark falling out of the sky and landing in the middle of the clearing put an abrupt end to all other activity. The multibear and the beat up manotaurs fled at the sound, leaving just the three exorcists and the Pines twins to see what, or rather, who the new arrival was.

Lenalee rose gracefully from her crouched position, completely ignoring the crater her boots had created. She took a second to straighten out her dark green hair, and then she turned a glare on her comrades that made all three young men swallow. They all prayed that they wouldn't be the target of her anger, and it was Allen who lost that battle.

The angry Chinese woman took a step towards the white haired teen and frowned at him. "Allen, you were supposed to be back by now. I came because I thought you needed help, but instead I find you goofing off. You're in charge of these guys, you should have told them to head back."

He just snorted at her words. "Since when do they listen to me? I can't make them do anything, and you know it."

Lenalee shook her head and crossed her arms over her chest. "That's no excuse. You should have tried harder."

Allen's response was cut off by Lavi and Kanda snickering, and the redhead laughed outright before he spoke. "Well Bean Sprout, looks like your girlfriend wears the pants in your relationship."

Lavi's laughter died under the glare Lenalee shot his way, and that made Allen laugh. "Oh? You seem to be more scared of her than I am."

He and Lenalee laughed at the scowl the redhead gave them, but any further taunting between the exorcists was halted by Dipper and Mabel as they began babbling excitedly over how awesome Lenalee's entrance was. The good natured Chinese woman took their excitement in stride, and at their request, even did a couple gravity defying acrobatic flips with her boots. But Lenalee wasn't one for showing off, so she quickly steered the conversation back to returning to the portal.

The six young people laughed and joked as they walked through the woods together, but their conversation grew quieter and more somber the closer they got to the portal.

Dipper and Mabel tried to convince their new friends to stay a little longer, but the exorcists knew that they had to return to their own time. Still, they were reluctant to leave and had a hard time saying goodbye to the twins. Tears were shed as the four teenagers stepped through the portal, and Dipper and Mabel watched sadly as it closed behind them, too upset over the goodbye to even think about following them.

Elsewhere, in the attic bedroom of the Mystery Shack, a green glow began to radiate from the grappling hook that was so carefully stowed underneath the pillow on Mabel's bed. What began as a soft glow quickly brightened to a shine that illuminated the entire room. Seeing the weird green light underneath the door from where he was sweeping the hallway, Soos set aside his broom and went to investigate. The light vanished as he opened the door, and the handyman gave the room a cursory glance. Seeing nothing out of the ordinary, he shrugged, closed the door, and returned to his work. After all, compared to everything else he'd seen that summer, there was absolutely nothing noteworthy about a strange green light.