A/N: This story will contain the following at some point or another. Be warned if any of these are triggers for you;

Torture (mentioned), body horror, blood and gore, and death.

It was strange having a great uncle that was only thirty years old but Dipper and Mabel had experienced stranger things. At least the man's youth made sense considering he had been spirited away to an alternative universe where time had undoubtedly progressed at a slower rate or had been inexistent. The one thing that left them puzzled in regards to that was that it had been four years since Ford's return and he looked the same as he did when he first returned to their world. It was like it had happened yesterday but Mabel and Dipper were sixteen now. The ongoing theory was that travelling to an entirely different dimension had stunted his body's aging. Why? They would likely never know.

Four years had passed since their first chaotic summer in Gravity Falls. The world had come close to ending but had been saved. The evil demonic triangle known as Bill Cipher was defeated and likely dead. And though the Apocalypse had been avoided, Gravity Falls refused to become even the slightest bit normal. Gnomes attempted every month to usurp Mayor Tyler Cutebiker, thieves continued losing their hands, and the mini golf attraction was still the most dangerous place to be after dark. It had been four years and the twins still had their hands full with protecting Gravity Falls one memorable adventure at a time. Little did they know their strangest and consequently most perilous adventure was just underway.

A lot of things had changed over the years. For one thing, Stan and Ford had mostly fixed their relationship. They got along fairly well and Ford had offered to let his brother stay and continue running his scam at the end of their first summer. The only times they ever really got into arguments was when it was a question of the supernatural. Ford would often venture into the woods with the twins to capture or study various magical animals, which Stan severely disapproved of but it wasn't like they could be stopped. No matter how much the old man protested and argued that it was a terrible idea, they went through with it all the same and whatever catastrophe happened while they were out was always dealt with, with minimal injuries. There was really nothing to worry about.

That being said, today, Dipper and Mabel were in the Mystery Shack. They were in the living room, watching TV while Stan worked the shop and Ford buried himself in more research down in the basement – he always spent most of his time in his lab. The sky outside was grey – almost black – and the rain drops pelted the windows so hard Dipper was sure the glass would shatter. The wind roared so violently it shook the house and the pine trees. Why did the people visiting the shop even bother leaving their homes with such a storm brewing outside? Surely they were insane…

And as the thought crossed Dipper's mind, someone knocked at the door. The twins tore their gaze from the show they were watching and glanced in the door's direction upon hearing the feeble sound mostly drowned out by the bad weather. However, they had been hearing similar knocks frequently because of the storm and were quick to dismiss it. Only when the person knocked again with more force did they jump from the couch and run to the door. Who could it be? Who would it be? Wendy would never leave her home in such weather. Neither would Candy and Grenda. Soos might. Was it it Soos?

No.

A young man stood in front of them and what a dashing creature he was. Soaked to the bone, his golden hair stuck to the sides of his face, his dark skin was covered in droplets but, more notably, mud and blood. He wore nothing but a tattered rag dirtied with the same things as his exposed flesh. His legs seemed particularly damaged what with the multiple lacerations knees down, dyeing the mud crimson. It was like he had been running through the woods and the dark bags beneath his amber eyes seemed to indicate he had been living hell for days. Weeks even. He seemed startled or frightened – maybe both. Had he been chased?

"Uuh…" The twins said, lacking the ability to utter proper words.

"Pine Tree, Shooting Star." He said giving each of them a nod. His voice breathed familiarity that wasn't quite as obvious as it should have been considering the nicknames he had employed.

"Who…who are you?" Dipper asked, unable to believe the conclusion he had come to unless the other man confirmed it.

"It's me." He said and he sounded as exhausted as he did desperate, "Bill."

"Bill!?" Mabel cried and her brother was too stunned for words.

"I need your help."