Welcome fellow Fallers! This fic will contain spoilers for everything related to Gravity Falls up to "Dipper and Mabel vs the Future." And maybe even past that. That aside, enjoy!
Dipper was busy with dusting some of the shelves at the back of the store. It was an abnormally dull day for Gravity Falls: Wendy was doing some light reading at the register, Soos was in the middle of changing a light bulb, Stan was going through some paperwork, and Ford was down in his lab, where Dipper was banned from at the moment. The only one missing was...
"Hey guys," Dipper asked aloud, "Have you seen Mabel running around? I just realized I hadn't seen her all day. She was gone before I got up."
"Beats me dude," Wendy shrugged. "I thought she was with her two b-f-f's."
"I saw her in town on my way here," Soos answered, "She was talking with someone. I thought it was you."
"What? Soos, I haven't left the Shack all day. Who was she with?"
He stepped off the ladder. "I don't know, dude. Want me to drive you into town so we can check it out?"
Dipper thought for a minute. What if it was just one of those things where Mabel found a new boyfriend? She found one in the thirty minutes it took him to find the journal at the beginning of the summer. Surely, it couldn't be anything serious right?
"You go ahead dude," Wendy said, "I'll cover for you."
"Thanks," he waved her off, "It's probably nothing anyway. We shouldn't be more than a few minutes."
Wendy gave Dipper a thumbs up on his way out the door. They drove into town, checking the stores and windows for the crazed twelve year old. It wasn't long before they spotted her.
"There she is," Dipper sighed with relief. With Bill on the loose, and all of Ford's talk of dimensional rifts in reality and what-not, Dipper had feared the worst had happened. Now he was never going to hear the end of it from Mabel about what a paranoid little freak he was.
"Why is she going in there?" Soos wondered aloud.
Dipper looked at the building and saw what he meant. It used to be Gideon's warehouse of merchandise, but since he got the book thrown at him, it been abandoned. Dipper wasn't really sure if any of that old stuff was still in there.
"I'm gonna head in," Dipper told Soos, "Give me, like, ten minutes."
"Got it, dude," he said, "If you need me, I'll be right here, playing the newest album of Bass Blasters, the loudest techno rock band of the 80's."
Dipper shook his head and shut the car door behind him. Soos will be Soos. He entered the warehouse as cautiously as he could. Mabel was nowhere in sight, and he could hear someone talking somewhere in the maze of boxes strewn about the warehouse. A shiver went up his spine, just grab Mabel and get out of here.
"Mabel?" He called out, "Mabel...? Come on, time to go home!"
He walked down the aisle for a few minutes before she appeared before him.
"Ah Dipper," the girl said before him, "Such a loving brother, such bold mind, but you can be such a simple fool sometimes."
Her voice sounded familiar, but the tone was way, way off. She looked like Mabel, but she seemed completely different. Her signature sweater, skirt, and overall happy aura was gone. Instead, Mabel had a light blue blouse with a black skirt, she wore high heels- which seemed weird enough for Dipper- and even wore a tiny cape over her shoulders.
"Mabel?" Dipper looked her up and down, "What on earth are you wearing? And what's with the accent? Summerween was last month."
She glared at him.
"I mean, not that it doesn't look good, or anything," he tried to recover, "it's uh... very fancy. Very nice. It just looks like..." The thought came to him as he spoke, "...Gideon's stage outfit."
"Ugh. That little twerp," she rolled her eyes, "That...adorable little twerp. I'm insulted, yet intrigued. Did you hear that, Brother?" She called over her shoulder, "Our outfits belong to one Gideon Gleeful here!"
Dipper wanted to wake up now, now more than ever. Because another Dipper stepped out from behind some other boxes. He held a black book under his arm, marked with an upside down Triangle on the cover, labeled with the number 2. He wore a shirt, pants, and dress shoes that matched the Mabel from earlier. His hair did little to cover the birthmark on his forehead. How could two people have the same, exact birthmark, in the exact same position on their person? It's not just improbable.
It's impossible.
But none of that mattered. He lead the Mabel Dipper knew in front of him. She had her pink sweater on, and her usual aura of bubbly kindness was replaced by fear and tears down her cheeks. She was unable to move or speak, due to the glowing pink ropes that tied her arms to her chest, and wrapped up around her mouth.
The other Dipper held one end of the rope. Dipper balled his fist and took a step forward.
The imposter pulled on the rope. "These ropes are the Katariam Restraints'. I can tighten these ropes upon command and snap your sister like a twig. Take another step and I will show you."
Dipper forced himself to stop. Mabel looked so scared, so terrified; he wanted to sock the two kidnappers in their respective jaws. He took a breath and put his hands above his head.
"Alright," he said, "You got me, what do you two freaks want?"
"Your lives, for one thing," the Evil Mabel answered snidely.
"Now, now, Mabel," the Evil Dipper calmly chided. His voice and his eyes were emotionless, no pleasure or regret for his actions. "We cannot kill them. We are still unfamiliar with the rules of dimensional travel. We could suffer trans-dimensional backlash for-"
"Yes, yes, yes," Evil Mabel waved her hand at him, "Your nerdiness is quite adorable, and useful, but I can hardly stand it."
She turned her attention back to Dipper. "Now come here Not-Brother-Dear. We have a surprise for you and your sister."
They led them slowly to a more opened area of the warehouse. They lined them up in front of a wall.
"Sister Dear," Evil Dipper asked, handing her the book, "Would you like to do the honors?"
"It would be my pleasure," she answered, taking it graciously and flipping it to a page. "Latrop eht Nepo. Latrop eht Nepo. Latrop eht Nepo!"
A swirling vortex opened before Dipper and Mabel. They couldn't react fast enough. The floor disappeared from under their feet. The only thing Dipper could do was hold on to his sister as they tumbled into the unknown.
"Have a nice trip!" The Evil Mabel waved, "See you next Fall!"