The humming continued to rattle underneath the flooded foundations of the town, as an unseen locomotive, wheels soaked in the waters of Lake Gravity Falls, spiralled along in deep subterranean tunnels, jarring on kinks in the rail and scraping against an ever-tightening helix of chamber and tube.

"I think I'm gonna be sick…" Marcus groaned, gripping the cab's side. "It feels like it's been hours…"

"Tell me about it, man." Wendy sighed, having sat in a corner of the cab and now brushing her hair in a distinct expression of boredom.

"I hope nothing crazy's going on up there."

"It's Gravity Falls, dude. It feels like some crazy garbage happens basically every twenty-four minutes." Wendy huffed. "I'll just be happy when we get back outside again."

"Gotta happen eventually, right?"

"If not I guess we gotta dig our way out, huh?" She smirked, climbing back up to her knees and giving her brother a friendly punch in the arm. "Think you can handle that?"

"Could dig my way to China if I wanted to." Marcus smiled with his usual earnestness, flexing an arm. "Don't worry sis, I'll protect you."

"Protect me? Jerk!"

"Noodle legs."

"Pinhead."

"Uh… noodle arms."

"Nu-uh, you gotta come up with something origi-" Wendy started, but trailed off as something caught her eye.

Behind the errant engine, the rails - reacting with the lake's water - were beginning to glow and throb, a hum reverberating through them quietly, but so significantly that they swore they could feel it in their teeth. Before Wendy and Marcus's eyes, the tunnels were lit up in a brilliant electric blue.

A blue that seemed to punctuate the entire summer. A blue Wendy had grown so familiar with, much like the Pines. The blue of Bill Cipher's fire - of Curzon Cankerblight's blood - of the Boggles and their mutated burning.

She furrowed her brow and tried to think of her next course of action - only to be interrupted. The engine bucked another rail joint and slammed against the track, causing the wet rails and soaking wheels to only illuminate brighter. Then again moments later. Then again. And again. As if it was some kind of gigantic music roll from a player piano.

The engine accelerated and the beat seemed to pick up, a sort of echoing, dull chant of rumbles and thumps, a paddler's beat that shook the tunnels and rattled the teeth of the train's increasingly confused crew.

Sparks flew from the wheels as they took another steep turn, the engine's thunder echoing into a kinetic, industrial percussion as steam whistled from the locomotive's tired cylinders. If it had the ability to talk, the great hulking machine would no doubt voice its frustrations about being on its second frenetic runaway in what had only been a few weeks on the job.

The gradient steepened, and to the sibling crew's horror, continued going down rather than up. Was there any way out of the damned place? Was there an escape? Surely it'd have to leave the ground eventually. Marcus - far from the brightest axe in the woodcutter's shed - was beginning to consider how long it'd take to actually dig their way back into the town's centre, while Wendy was trying desperately to peer through the engine's windows and work out where they were even going.

On the surface, the ever-prepared Quentin - donning a suitably old-timey ear trumpet that he had coated in pony stickers - was listening intently. "It's happening."

"What?" Ford asked. "What's happening?"

"The thing, by thunder! We have to travel to the Manor. I fear that a great evil is approaching. Nathaniel Northwest is making his move."

"The guy's a mess of arms." Stan retorted. "What's he gonna do?"

"A man with many arms can cause many harms, my wrinkly friend!" Quentin replied, with a look of raw pride on his face.

Stan blinked. "...Ya think of that all by yourself, chief?"

Quentin twisted on his heel and changed the subject in a heartbeat. "Pines! We must go! We must most definitely leave Pacifica Northwest and never think of her again! She is in good hands! Richer hands, ergo better!"

Pacifica raised an eyebrow, still restrained by her mother's quivering claw. She wasn't really sure if Nathaniel was about to do something - though she had little reason to doubt it - or if Quentin was just being a melodramatic weirdo trying to stage a distraction.

"Good! Leave! Get away from us! Get away from my daughter!" Priscilla screeched, still threatening with her stiletto heel.

Huh. If it's the latter, it's working.

"I've no intention of doing anything else, my dear." Quentin retorted, placing the ear trumpet to his mouth - much to Dipper and Mabel's recoil - and giving a deafening, highly accurate goose call. It echoed across the flooded valley, deafening even the hammering of rain.

HOOOO-OOOO-OOOO-OOOO-OOOONK

The trees seemed to shake in the deep, avian sound wave. The water rippled. The earth shook, as - with the beat of gigantic wings, and a beak as bright as the hottest flame, the enormous bird descended over the town. Gooseliath. At this point, the Pines were so used to the sight of the thing that they barely batted an eyelid.

The townspeople, however, were far more startled. They stared, eyes fixed towards the great gamey breast of the creature as its serpentine neck and wrenching webbed feet towered above them, threatening to graze buildings.

People backed away for security, while Preston clambered aboard one of the webbed feet and climbed his way to the circling bird's upper echelons. The sight was monstrous - after all, everybody was at least a little cautious around geese - but not a soul could look away.

The outsized waterfowl landed comfortably in the water as if the entire town was little more than a boating lake. Just when it was beginning to eye up the local bakery with a fierce, hungry glare in its outsized beady eyes, Quentin steered it towards the roof of the courtroom and barked at the Pines to come aboard.

The family did so, bounding from the soaking roof and clambering onto the goose via an outstretched, enormous wing - while everybody else was frozen in a mixture of sheer confusion and fear. How was one meant to react to a giant, distinctly fierce-looking goose? Those pin-teethed devils could break an arm at a normal scale. This thing looked like it could break a Dan.

Priscilla and Preston, watched, slack-jawed - which gave Pacifica her chance.

The Northwest socialite looked at her mother and her father, both of whom had been momentarily distracted - as one would usually be - by a gigantic, flapping menace with a president on board. Then, she made her move - a move that was most unbecoming of a Northwest. Pacifica bit hard into her mother's perfectly pedicured hand, ripping free of her arms as Priscilla recoiled and screeched furiously.

"Y-you brutish little cockroach! You disgusting little worm!" Priscilla snapped. "A-a-a Northwest! A Northwest resorting to biting!"

"Pacifica, get back here right now!" Preston roared. "I'm warning you!"

Pacifica turned to them and scoffed. "Get bent, Dad."

In the moment that followed, the rest of the town acted. Dan wrestled away Priscilla's threatening stiletto from behind. At the same time, the cops raised their tasers, Tad Strange a particularly crusty-looking baguette, Soos a bag of cable ties and Susan her rolling pin, stepping forward in a clear show of force.

The two wealthy, woefully unfit parents froze and rose their hands in submission, faces as thunderous as the blackening skies above them. Until they were off of the roof, at least, they were trapped by the simple people of the Oregon town that they so detested.

Pacifica vaulted over the roof trim and skidded down the gabled slope of the courthouse haphazardly, taking the odd roof tile with her before she clambered hurriedly over the bird's wing, threw herself at Dipper and clung to him as tightly as she could, out of breath and - rightfully - upset.

Dipper wheezed and looked up at the outraged scowls on the face of - well, he guessed his future parents-in-law? Wait, did he seriously just think that? Man, Mabel must be rubbing off on him…

He squirmed in her vice-like grip and held her back as warmly as he could, trying to fight off the red in his cheeks as she buried herself in his neck. "I-it's o-okay - it's okay Paz, I get it-"

"It's like she's gone insane…" She whimpered through a wobbling lip. "What are we going to do?"

"My friends;" Quentin replied. "If my theory is correct, that water's going to cause terrible problems for us. And if Nathaniel is heading over there, you can guarantee it's for trouble. We have a strange, crooked sea-urchin-man to destroy!"

"T..that wasn't what I meant."

"I am if nothing an immensely practical man!" Quentin declared, while chewing a honey-roast salamander he had apparently kept underneath his shirt collar.

"You think we might need some extra muscle?" Ford said, looking at the kids with a certain…concern. Three barely-pubescent kids, each barely a whisker above 5ft tall - it wasn't the most imposing army.

"HEY!" Stan yelled. "Corduroys!"

The Lumberjack and his sons looked over.

"Ya got a chip on yer shoulder 'bout these guys, right? Wanna avenge Archie?"

"Ohmygoshyes!" Mabel said excitedly as Kevin clambered aboard with his family. "We're gonna kick butt together!"

"Wrinkly, smelly, half-rotten old man sea-urchin butt!" Kevin beamed, embracing her.

Dan just stepped aboard, threw off his bizarre 'courtroom bow tie' and sniffed in appreciation towards Stanley and Stanford. There was even a quiet respect towards Pacifica. He had been fairly obvious in his preference of them versus the Northwests.

Probably fuelled by the fact he was exactly the sort interested in taking down a rich jerk.

"The final match-up of the century!" Quentin bellowed. "Corduroys VS Northwests! It's positively Shakespearian! Onward, Gooseliath! Onwards! We must get to the ballroom on time, my dear!"

Dipper watched the typically unhinged blathering of Quentin Trembley and twisted his lip. Slowly, he leant over to Pacifica and whispered. "Did you pick up the stuff from Nathaniel about secret agents?"

"Kinda dealing with generational trauma right now, Dip."

"R-right, right, sorry, I uh - I get it, I-"

She giggled, wiped her eyes, and kissed his cheek. "Yes. I heard it. But maybe we focus on saving the world first, huh? One big conspiracy at a time."

"Got it." Dipper smiled, rubbing the back of his neck. "Do you…need another hug?"

"You have absolutely no idea." She replied, squeezing him like a boa constrictor.

The Gooseliath took to the skies, much to Gus's delight, and left the townsfolk encircling the Northwests who - for all intents and purposes - had just found themselves on the very edge of the town's patience, and the very edge of the courtroom's roof. A doubly bad time, really.

Pacifica wiped her eyes and looked out at the flooded town. The town that, for all intents and purposes, she had fallen very much in love with. It seemed barely the same. Decimated. Half-underwater. Post-apocalyptic. And with that strange, ethereal glow, it only seemed to grow stranger, more offputting, more…

Wrong.

She looked up at the Pines and the Corduroys - scrappy people, waterlogged, rough around the edges - she was pretty sure that Gus swore even more than Stan did - but good people. Honest, caring people who were dedicated to doing the right thing.

People who helped Gravity Falls.

And as she searched herself, she realised how much she felt like one of them. She wasn't perfect, but she was a whole lot better than her family. And that was enough.

They may have been flying into the great unknown, but she was feeling more certain of her choice than ever. She'd do anything that'd result in Nathaniel and his… his weird form of madness being taken away. She would do anything to see the town back to how it was meant to be.

And damned if she was going to let her parents get in the way.