A/N: During the story, I will be switching between the POV's of Stan, Stanley, and Fiddleford.

Chapter One:

Welcome to Gravity Falls

"This is Gravity Falls? Ha, more like Snooze Falls.", a man in a white shirt, rolled-up jeans, and slicked back brown hair laughed as he looked around at the sleepy town of Gravity Falls, Oregon.

"Why'd you even wanna come here, bro?", Stanford Pines asked his twin, Stanley Pines, who was looked like his complete opposite (minus their facial similarities) with a black T-shirt, grey sweatpants, and messy brown hair.

"Because.", Stanley said simply as he drove on, moving past the town and into the woods.

"Because why?", Stanford asked.

"Just because.", Stanley shrugged. Stanford punched his twin in shoulder, startling him.

"Watch it! Do you want us to crash?", Stanley snapped as he got back in his lane. Shrugging, Stanford went back to staring out the window. Tree... tree... boulder... tree, he thought in boredom as he looked out at the passing scenery, tree... monster thing... tr- wait what!?

"Stop the car!", Stanford shouted.

"What!? What's wrong!?", Stanley yelled as he slammed on the brakes. Jumping out of the car, Stanford looked around for the beast he had seen, then felt his jaw drop as he spotted it. It was 7 feet tall with dark green skin, light green underbelly, and giant fangs and pointed ears. Moss, hair, and toadstools grew along it's back and arms, and it's eyes were blood red.

A/N: Just in case some of you didn't understand my description, the monster is a Gremoblin.

Deciding to avoid the eyes, Stanford looked into the car and said, "Lee! You have to check this out!"

Unfortunately, the beast heard him and looked over at the car. In a moment of panic, Stanford picked up a rock and threw it at the beast, which only angered it enough to charge the car.

"Drive drive drive!", Stanford shouted as he jumped in the car. A moment later, they were off, since Stanley had not only heard, but had seen the beast as well.

"What the hell is that!?", Stanley yelled.

"Just shut up and drive!", Stanford exclaimed. He looked out the window and was horrified to see that the monster was hot on their tail. I have to do something! A second later, a bottle of water flew out of the passenger window, bursting against the monster's forehead. Sadly, this only seemed to help the beast, who grew another foot and sped up.

"You made it worse!", Stanley exclaimed.

"I know, I know.", Stanford growled, looking around for a weapon of some kind. Looking up, Stanford saw a tree had fallen in the road and yelled, "Lee, look out!"

Stanford felt himself lurch forward as Stanley slammed on the breaks. He also felt his head hit something hard as the car slammed against the tree, thankfully only destroying the front half of the car. The last thing Stanford saw before he blacked out was the monster approaching them slowly, like a lion hunting downed prey. Gee, what a great thing to imagine before I die, Stanford thought as he slipped into darkness.

A/N: The story is now in Stanley's POV.

"Ugh... What happened...?", Stanley groaned as he woke up, finding himself face down on the air bag. Looking around, Stanley discovered a small stain of blood on the dashboard and an empty passenger seat. Where's Fo- the monster! Stanley thought in shock as he remembered what had happened. Ford must have hit his head on the dashboard when we crashed! After crawling out of the car through the passenger window (thanks to a large branch blocking his door), Stanley slumped to the ground, exhausted. Once he was able to, Stanley got up and looked around, trying to find some sort of trail or- There! He thought as he spotted a small trail of blood leading off into the forest. Without thinking, Stanley ran off in search of his twin.

After what seemed like ages, Stanley finally found a cave deep in the woods, riddled with the remains of animals (at least, Stanley hoped they were animal remains...).

"Ford!?", Stanley whisper-shouted into the cave. Receiving no response, he decided to go inside, but not before grabbing a large branch for protection. Just grab Ford and get out... Simple, right? Oh how wrong he was...

Once Stanley reached the main part of the cave, he found out that he was actually able to see thanks to a small hole in the ceiling, which let in the sun and lit up the small cavern.

"Ford!", Stanley exclaimed as he spotted his brother and ran over to him.

"Ford? What's... Ford!", Stanley exclaimed worryingly as he shook Stanford, who was slumped against a boulder, staring off into space with an expression of pure terror on his face. Suddenly, Stanley jumped up as he heard a growl coming from the shadows.

"What did you do to my brother!?", Stanley demanded as the monster came into view. It didn't answer, of course, since it was only an animal.

"Just leave us alone!", Stanley screamed as he threw his stick at the beast, who simply roared and charged. Stanley stumbled back and tripped on Stanford's foot, falling to the ground with a loud, "Oof!"

He quickly searched around blindly for something, anything that could be used as a weapon. His hands closed around something cold and smooth, so Stanley quickly lifted it as if it was a shield. Clenching his eyes shut, Stanley waited for the inevitable end of his and Stanford's young lives. When that didn't happen, Stanley risked a peek over his makeshift shield. The beast was just standing there, a look similar to Stanford's frozen on his face. Once he concluded it was safe, Stanley dropped the shield, glancing at it momentarily. A mirror? Fascinating, he thought, then shook Stanford again.

"Ford? Come on, snap out of it.", he pleaded, but eventually decided that he would have to drag Stanford out of the cave to the shack they had inherited from their grandparents.

"Ugh, you're heavier than you look.", Stanley groaned as he grabbed his brother under his arms and began to drag him out.

A/N: Stan's POV.

Stanford was having the nightmare of all nightmares. He and Stanley were standing on a cliff, surrounded by their childhood bullies, who were now 2X their normal size, and Stanford had been forced to watch as they slowly but surely killed his brother. Just when Stanford thought that he would die from pure terror, someone dumped a bucket of ice water on his head.

"Son of a BEEEP!", Stanford cursed in shock as he jumped up out of the fold-out chair.

A/N: Sometimes, it's best just to beep it. :)

"You're okay!", Stanley exclaimed as he embraced Stanford in a bear hug.

"Course I am! Why the hell did you do that!?", Stanford exclaimed as he wormed out of his grip.

"You weren't responding to anything I was doing. What happened to you, anyway?", Stanley asked.

"Nothing. Nothing at all.", Stanford grumbled, turning away.

"Stanford, what happened?", Stanley asked again as he put his 6-fingered hand on Stanford's shoulder. Stanford sighed in defeat and said, "All I know is that one minute I'm looking at that... thing's freaky eyes and then all of sudden I'm watching you... I'm watching some hellish nightmare."

"So... That creature can make you see your worst nightmare?"

"I guess."

"Interesting... Ford, I know we came out here to work on our careers, but I think we should do something else."

"Oh yeah, like what?", Stanford asked as he turned back around.

"I have a feeling that monster wasn't the only supernatural thing in this town, and I want to find out more. Perhaps we could be... I don't know, supernatural detectives?", Stanley said as he rubbed the back of his neck.

"... Mystery Twins.", Stan said after a moment.

"Pardon me?"

"That's what we'll call each other. The Mystery Twins."

"Hm... Well, it is catchy... Alright then, it's decided. We are now officially the Mystery Twins: Secret Detectives of Gravity Falls."

"Awesome. Awkward sibling hug?", Stanford suggested as he held his arms out. Stanley grinned and said, "Awkward sibling hug."

The twins hugged each other, then patted each other on the back while saying, "Pat. Pat."

A/N: I couldn't help myself! XD So... What did you all think? Please review, favorite, and love Gravity Falls! 3

PS: I got the idea that Stanley and Stanford like to refer to each other as Lee and Ford from one of my friends on Tumblr. :)