Yeah, so, hi! My first crossover fic! I, uh, don't own RotG or GF. and there are no OC's in this that I know of (my brain works in mysterious ways) so... I own nothing *jaw drops in shock*. Woooooowwwww... awyways, enjoy

I would say once upon a time, but this isn't a once upon a time sort of story. And, spoiler alert, this story doesn't have a happy ending. So, I'll say something else.

Twice under a knitted sweater, there was a girl named Mabel Pines. She was the sweetest, most bubbly girl you could ever meet. At sixteen, she was still in touch with her inner child, curious, imaginative, and, overall, troublesome.

Mabel wasn't your ordinary teenager. Most teenagers had hormonal problems, giving them constant, violent mood swings. Mabel didn't have that, her violent mood swings were 125.7% her. She didn't have acne. She didn't have oily hair. She didn't have to try to look beautiful, that happened naturally.

And it was one of the reasons she was hated most in the sleepy town of Gravity Falls.

When she was twelve, Mabel and her twin brother, Dipper, went to Gravity Falls for the summer. Located in the very center of Oregon, it was almost completely unknown. The only things keeping it on the map were the Tent of Telepathy, the most popular attraction in Gravity Falls, and the infamous Mystery Shack.

Considering Mabel has the perfect life, she must have lived at the Tent of Telepathy, right? Well, no. Actually, she hated that place. Her ex owned it, Gideon Charles Gleeful, who had tried to kill her and her brother, mostly her brother, on multiple occasions. She worked and lived at the Mystery Shack, the weirdest, wackiest, and most likely dirtiest place on Earth.

The summer trip had started out like any other- they needed fresh air and sunshine, blah, blah, blah, too much time indoors, yada, yada, yada... well, that was four years ago. Back then it was an innocent little vacation. Then, about three months later, it took a turn for the worse.

Mabel and Dipper were on their way back from Gravity Falls. Mabel was crying, shouting in protest about how unfair it was she had to leave her pet pig, Waddles, back at the Shack. Dipper was trying to speak over her, recalling his many adventures from the town. Mrs. Pines was attempting to sleep, while Mr. Pines was yelling his favorite song, We Are Young, above it all. In other words, a normal Pines family road trip.

It was Dipper that saw it first. The truck. It had lost a wheel, its engine was on fire, and it was spinning out of control. He screamed, pointing out the window and yelling in alarm. They were right in its path.

The noise drowned him out. Mrs. Pines had started snoring, and Mabel was trying to sing along to the song.

"Today- uh, Tonight, we are old, um, young~!" She cried.

Dipper shook her shoulder. "Mabel," he shouted, "Mabel, look!"

He pointed out the window. Mabel paused and glanced out at the truck, which was a yard away. The twins screamed in unison, finally getting their parents attention. The two heads of the Pines parents swiveled to the left, where the truck was less than a foot away.

Dipper threw over his backpack over his back. Mabel took her vampire novels and threw them over their heads. (A/N: NO PINECEST INTENDED IN THE FOLLOWING!) Dipper grabbed his sister's arms and pulled her in close.

The parents yelled in horror, the truck only inches away. Mr. Pines grabbed his beautiful wife and tried to shield her. He slammed his foot on the gas to outrun the truck, the speed limit thrown to the wind. The entire family of brunette's screamed in terror as the truck smashed into the side of the car.

The music continued.