The sky was just beginning to shed shades of pink and orange when the car halted in front of a refurbished wood cabin. It was just like the photos the twins saw online, with the words "Mystery Shack" displayed on huge yellow boards across the roof. The "S" in "Shack" looked a little loose, and Dipper wondered if Stan had noticed.

As they got out and stepped up to the main porch entrance with their bags, Dipper saw the gift shop jutting out of one side of the house, as well as the weathervane with the letters W, H, A and T circling around a red question mark. The whole structure stood in a clearing in the middle of the woods, the branches catching the light of the sunset to mix orange and yellow with darker greens and blues. The surroundings certainly looked like something out of a fantasy book, a place where strange things could wander in and out of the bushes. The interior however, soon swept away any mystical atmosphere.

"Welcome to your home for the next three months, kids!" Stan greeted cheerfully as he unlocked the front door. Inside were half-finished, barely-lit displays atop wooden pedestals or inside glass cases, engraved with such labels as "The Punchin' Munchkin" and "Man's Head from the Forgotten Zombie Apocalypse." The whole interior smelled faintly of glue and varnish. Dipper bit his lip to stop any comments that could get him sent straight back to the bus stop, and he turned his attention on exploring the "attractions" some more.

"Dipper, check this out!" Mabel pointed to a row of jars, each filled with large, most certainly fake organs floating in strange green liquid. When he spotted a jar filled with eyes with smeared painted irises, Dipper questioned just how Grunkle Stan kept this shop for so long.

"Mind you, everything's still kind of in a rough stage. The shop doesn't technically even open 'til next week," Stan called out from behind a half-open door to the side, near a wax figure of a deerskin-covered centaur. Dipper followed his voice and saw a tiny kitchen, along with a small table set up with three chairs. Even this part of the house looked tacky, from the stuffed wolf head on the refrigerator to the old-fashioned stove in the corner. Everything felt out of place and out of time, and he wondered if that had anything to do with its owner, now rummaging through the fridge.

"Uh, you two up for some bacon and eggs for dinner?" Stan offered.

"Alright, breakfast dinner! Brinner!" Mabel cheered, running past Dipper as Stan got out a frying pan and some butter. Dipper circled around them to deposit the neglected egg sandwich and some other leftovers in the fridge. Its near-barren state made him predict that he and Mabel might be repeating their brinner tomorrow morning. He closed the fridge door while rubbing his frowning temple, and returned to the Shack's showroom.

Since the Mystery Shack wasn't back in business yet, he ventured that none of the employees were around either. He then wondered just who would want to work around decades-old taxidermy and papier-mâché body parts, and if anything Stan paid them would even compensate-Alright, alright, you've barely even been in this place for five minutes. You wanted to go somewhere different, remember? he chided himself. Turning his head, Dipper was struck by the most brightly-lit part of the shop: a wall featuring a three-by-four glass display of colorful insects and arachnids, each labelled with strange monikers like "The Bermuda Bloodsucker" and "The Brown Widower." What really drew his attention however, was a butterfly nearly as wide as his handprint, its dark wings streaked with black and red dots. He read the golden label out loud.

"The Addy Snatcher?"

"Eager to hear that story, aren't ya?" Dipper felt his shoulders jump as he turned to face Stan. For such a huge man, he'd come up to him as quiet as a mouse.

"Grunkle Stan, is there something special about this butterfly? I mean, just six of them had a fancy cage to themselves and even this one's right in the middle of the display. It's not even the biggest bug here," Dipper said, waving his hand at an impossibly giant red beetle on the top-left corner.

"Believe it or not, that bug's got a story that goes all the way back to the beginnings of this town," Stan regaled, tracing a finger over the glass.

"Really?"

"If you catch one and hang it up by your window, it'll scare off crazy old Addy when she tries to get inside your head," Stan elaborated, pointing to Dipper's forehead. His straight if yellowed grin promised a gruesome tale.

"Who's Add-… is something burning?" His nose cringed at the dark, smoky scent of overcooked oil and meat. Stan gave a sniff, and his showman facade dropped in a snap.

"Be right back!"

He ran straight to the kitchen, where he loudly tried to assure Mabel that they didn't need the fire extinguisher. Dipper fanned the air with his hand to get some of the stench out of the way. Judging by how recent the smell was, the worst thing to come out of this would be charred pork.

So he instead turned his focus on Stan's mentioning of "crazy old Addy." Was that some sort of local legend? Whatever it was, if Stan knew he could make a buck off of the story, he had to have something related to that in the shop other than a butterfly you could buy somewhere else. Dipper scanned across the displays again for anything he missed. Just as he tilted his head up, something seized his eye.

Right above the main door was an oil painting, barely visible through the dim lights and the shadow of the ceiling. A woman sat primly on a high-backed chair, auburn hair tied back into a bun exposing the white streaks forming from the roots. Her high-collar black dress starkly contrasted with her sallow skin, as well as her sunken yet startlingly bright green eyes. The artist seemed determined to highlight those particular features, along with the circular silver locket around her neck.

"Pfft, thanks for coming in to help, Bro," he heard Mabel deadpan as she walked over to him.

"Hey, if I did, I'd have just given you an excuse for you to say some 'saved our bacon' pun."

"Remind me to save that one, actually." Mabel responded sincerely. She glanced up, and was similarly a bit thrown back by the painting's presence. "Who is that?"

"If I have to guess, crazy old Addy," Dipper answered.

"Hey now, is that how you greet all your ancestors?" came Stan's voice.

"Wait, what?!" Dipper jumped, not so much out of surprise that Stan had snuck up on him again, but how casually he had delivered this little bombshell of information.

"Yeah. Up there's Adeline Finn Pines, widow of your great-great-great uncle, Abraham Pines." He had on his gleeful, ominous smile again, and it worked to bait the kids into his tale.

"No way!" Mabel exclaimed.

"She's… what? So wait… why was she called crazy?" Dipper stammered, squinting his eyes up at the portrait as if the answer would appear on the canvas.

"Oh, poor woman went nuts after she lost old Abe. Legend says that she turned to dark magic from her grief and terrorized Gravity Falls just when the town was trying to get settled. Eventually, they chased her out, but Adeline's ghost still lingered. No child could sleep soundly for nearly ten years, for fear of the green eyes of the crone Adeline turning their dreams into nightmares that could make a grown man's heart stop."

Dipper gave a nervous gulp. Mabel's eyes grew bigger with each word.

"But they were able to find something to cure their troubles." He calmly walked over to the glass display of bugs, the bright light casting a strong shadow across his grizzly features. "Behold, the-!"

"Yeah, yeah, what's the butterfly got to do with it?" Mabel interrupted, her knees bouncing.

"I'm getting there!" Stan muttered through gritted teeth. After clearing his throat, he promptly continued. "Those early settlers had never seen anything like the Addy Snatcher, and indeed, you can only find it here on Gravity Falls. Some say it's just a locally-spread mutation, but many at the time believed that it was a sign. Perhaps God had given them this strange butterfly to help them counter the demonic spirit of Adeline. And indeed, the more people put them up by their windows, the more peacefully they slept. It seemed that Adeline had finally left this earthly plane," Stan concluded.

"Or did she?!" he shouted, dramatically swerving his arm. He pointed to Adeline's portrait, as if she were to jump out of the frame and wreak unholy vengeance.

"Grunkle Stan, we just saw that painting," Dipper pointed out.

"I know, I know, but it's something I've been working on to use for the customers. So, what'd you think, thumbs up, thumbs down?" he asked earnestly.

"I can't believe it though! We're actually related to a witch?" Mabel exclaimed, her voice a mix of unmasked wonder and disbelief. She turned her head up to the portrait of Adeline with a slack-jawed stare.

"Eh, by a thinner strand than you think. She married a Pines, but never had any kids. Never remarried either. In fact, there's nothing left of her except for this portrait and some dusty records at town hall," Stan explained.

"So… what, people just made this story up about some lonely woman?" Dipper questioned. He looked back at the painting, Adeline's jewel-like eyes casting a tired, disapproving gaze.

"Well now, I did do some research on this. There's not a whole lot left, but there is a record of her trial, saying that she was declared guilty of some crime and exiled from town for it."

"'Some crime.' How specific," Dipper said blankly.

"Don't blame me, blame the backwater court system. Now c'mon, your eggs are getting cold."

XxX

"Hey, Mom!" Mabel happily greeted her pink-and-purple cellphone. She laid back on her bed in her polka-dotted nightgown, her legs propped on the headboard. She lazily swung her free left arm over one side of the bed, the other side being right up against the attic wall.

"Hi, Mabel. How've you been this past week?" came her mother's gentle if tired voice. She must have just gotten back from work.

"Oh, pretty great, actually! Now that the Shack's open for the summer, people come in here pretty much all the time."

"I see. Mabel, do you and Dipper spend a lot of time in the Shack?"

"Yeah, but we usually just hang around the gift shop with Wendy and Soos."

"Who?"

"Oh, Wendy works at the cash register in the gift shop, and Soos is the handyman. Both of them are super cool, like just yesterday, when I got my head stuck in a barrel, they were able to get me out with just a banana peel and a rusty nail!" Mabel recalled enthusiastically.

"…Really?" Her mom knew Mabel well enough that asking about the circumstances wouldn't make any more sense.

"Oh, don't worry, the banana was mine and Wendy was really careful with the nail." Mabel smiled, just imagining what kind of face her mother wore while processing this information. She was about 86% sure Dipper picked up his "I-Disapprove-So-Much-Words-Escape-Me" face from their mom.

"Well, it seems like you've adjusted expertly. How's Dipper?"

"He's fine…ish." Mabel answered hesitantly.

"'Ish?'"

"I dunno, I think he's still antsy about this place. All he does is just read and play video games in his room and mope about Wendy."

"What now?" She could hear her mom's voice tighten, but Mabel just chortled.

"Yeah, he's so obvious about it, I bet she knows too." The number of times Mabel picked up on her brother stammering around Wendy was ridiculous.

"And Wendy is-?"

"Don't worry, Mom. She's like, 17 and already has a boyfriend. But she's seriously nice to both of us, so I can kinda see where Dipper's coming from."

"MABEL!" A cracking, high-pitched yell from the attic door. Mabel automatically flinched and turned to see her brother, his face white as a sheet while his hair still strung wet from the shower.

"Whoops," Mabel uttered.

"Give me that! M-Mom?" Without even asking, Dipper strode over, swiped her phone and placed it over his ear.

"Mom, nothing that Mabel said was remotely true, so just ignore anything you just heard," he pleaded.

"Hey, not cool!" Mabel shouted.

"Yes, yes!" Dipper was now fully wrapped up in his own talk with their mom, both hands pressed hard against her phone.

"Okay, I got that. I'll call like, every night!" he agreed as if their mom had him tied to a bomb.

"Huh?" Dipper exclaimed, but then quickly nodded his head.

"Okay. I'll figure something out. Love you too. Bye." Dipper hung up the phone and turned to her with an agitated sigh.

"What?" she asked, aware of the accusation his sigh carried.

"You so owe me," Dipper replied, tossing the phone back to her.

"Come on, it was just Mom," Mabel assured him.

"Yeah, who's friends with Carl and Owen and Nathan's moms! If I didn't step in, she'd have just spread the whole thing, so that when I get home, all they're gonna do is talk to me about will be Wendy stuff!" Dipper jumped on his bed by the wall opposite her side of the attic, and buried his head inside his pillow. And people called Mabel the silly one.

"Dipper, relax. What did Mom even say about that?"

"Well… she said that she won't tell anyone if I call home once in a while, and if I find something to do during the day," he answered, voice muffled through the pillow.

"Sounds easy enough."

"Yeah, except I've been trying to do that last part all week!" Dipper turned his head to lay down right-side up.

"What? C'mon, you practically never go outside." Dipper's bed, messy with snack wrappers, his laptop, and an unwashed cereal bowl, was evidence enough.

"Well, while I was here, I did try to look up some things to do, but trust me, there's nothing. Not even some community college summer program," he explained, tapping one foot to his laptop.

"Really?"

"Well, nothing that looked interesting." Dipper sounded not so much dry as utterly lifeless, and Mabel rolled her eyes.

"You're just being picky. Tell you what: tomorrow, why don't we ask Grunkle Stan to take us around town, maybe stop by the mall for lunch?" Mabel suggested after brief deliberation.

"You think he'd be up for that?" Dipper asked, casting a doubtful look.

"The Shack closes on Sunday, so why not?" she reasoned with a shrug. She could see Dipper mulling it over in his head, but he came to an answer quickly enough.

"That… sounds good, actually," he conceded, but in an optimistic tone that conveyed how bored he really was from routine.

"Right? If it's a Mabel idea, nothing can go wrong," stated Mabel, her braces-wedged smile shining with confidence.

"Even yesterday's barrel incident?" For that, Mabel took aim at her twin's stomach with one purple teddy bear.

"Ah! My one weakness: smiling plush toys!" Dipper yelled in over-the-top agony, clutching at the stuffed object of assault.

"Oh, as if that's your only one! Tickle Tackle!" She jumped over from her bed to his, pinning him down with well-placed tickles to below both armpits.

"O —ahahahHAHA— kay, kay, Mabel —noHOhohohHOHO!— you gotta stop! I –Haha— can't breathe!" Dipper wheezed out, his laughs somehow sounding both giddy and pained.

"Admit surrender!" Mabel demanded, her face beaming fiercely. She inched away as her brother gulped for air.

"Alright, alright… I just need time for a counterattack!" Dipper yelled back. He didn't tickle her back, but took his pillow and smacked her over the head, then dashed to one corner of the room with a cocky smile.

"We're under attack! North flank, assemble!" she declared, gathering all the stuffed animals and pillows as she could from her bed and charging towards her brother.

Just as the pillow/stuffed animal fight escalated into a civil war with Porpoise Percy as the besieged king of a land of colorful cushions, Mabel heard the distant roar of thunder from outside. The twins briefly halted, and looked over to the triangle-shaped window between their beds. Rain started to come down in plinking, tiny droplets against the glass.

"The great storm has come to flood us all! Everyone retreat!" Mabel shouted with her arms in the air.

xXx

Under the cover of the thunderstorm, no one heard the drum-like boom of the new arrival in the woods. In a small meadow, from a glowing, white-blue circle drawn into the wet dirt, a peculiar spirit emerged, wide-eyed and silent.

The spirit, his glowing teal skin and hair frozen under the cold shower and building humidity, looked around like an animal caught in the headlights. He wanted only one thing: escape. Escape from the two darkly-clothed figures before him, who held steely tools and recited incantations in raspy murmurs.

Neither of them looked very big, certainly nowhere big as a healthy bog goblin. And try as they may, their spells were about as effective as spraying sand against a boulder. He bowed his head and closed his eyes in a false show of submission. He was really pinpointing his focus on the core of his lungs, the center of his energy. He felt the fire within, and so he tried to find fire elsewhere: a place of refuge deep within the hushed wood.

In his transcendent inner vision, the spirit saw a house, and he felt the fire of four souls… yet only three had living vessels.

Stranger yet, he recognized that odd, misplaced spark, one he had come in contact with ages ago. And it would be his key to returning home.