Mabel gasped and opened her eyes. She was staring up at the wooden ceiling beams and something was digging into her upper back.

"Ow ow ow..." she said while sitting up and picking out splinters from her hand. She looked around the room, her and Dipper' s room, and realized that she was where her bed should be. Mabel stuck out her tongue and raspberried at all the newly discovered wooden planks. I guess that means another sleepover with Dippy!

"Mabel, is that you?" someone's muffled voice moaned. It sounded a lot like Dipper. Mabel walked over to bis bed and poked whatever was under the blankets.

"Poke. Hey Dipper, what'd Grunkle Stan do to my bed?" She pulled away the covers, and Dipper stared back at her. His arm was clutched over his stomach, his face was a little green, and his hat was really messed up. It looked like a cat scratched up the little pine tree. "Hey, bro, you okay? Were you sleeping outside again?" she asked skeptically.

Dipper moaned again. "I'm gonna puke..." Mabel looked away until she was sure he was done. He lay back, his face more relaxed. Suddenly he brightened. "Hey, Mabel, you're okay!"

"Um, why wouldn't I be? I mean, like, we don't really share drinks that often. Poke."

Dipper blinked and frowned. "Uh... Mm-mm-mm. And I don't know what happened to your bed. Maybe Stan used it for some kind of cheap attraction? Last time I saw him he was grumpier than usual, so I'm guessing he was guilty or something." After he got up, he stared at the bed for a few second with a frown, but he shrugged and looked back at her. "C'mon, let's go get breakfast." He turned around, but Mabel placed a hand on his shoulder to stop him.

"Something else wrong?"

"Nothing's wrong," Dipper replied, but Mabel could tell from the look in his eyes there was.

She grinned. "C'mon, tell me! Tell me! Tell me! Tell-"

"I told you, nothing's wrong," he said defensively and shrugged her hand off. A pang of confusion and hurt pricked her, but she followed him anyways. Since when does he keep secrets from her?"I wonder if he made Stan Cakes again."

"Hope not," Mabel said as Dipper opened the door. Behind it was a surprisingly familiar face. "GIDEON!"

"What do you want?" Dipper said and looked like he was ready to punch.

Gideon frowned. "Uh, who-"

Mabel held her arms up. "ROUND HOUSE KICK!"

"What-WOAH!" Gideon ducked and fell, either from the kick or as a dodge, and Mabel high-fived her twin.

"Woah, Mabel, where did you learn to do that?" Dipper asked while she watched Gideon scoot away.

"I've been looking into ways to protect myself from Gideon," she bragged.

Gideon finally got up and was slowly stepping away. "WHO THE HECK ARE YOU TWO?!" Suddenly he froze and his eyes widened. "Oh no, you can't be..."

YES WE ARE! WE ARE THE AMAZING MYSTERY TWINS!

"I-I'm innocent-it wasn't me who wrote it! I just-" He took a step back and reached into his vest. A book fell to the floor with a loud thud.

"Gideon, is everything all right up there?" Grunkle Stan said from down below. Grunkle Stan? Grunkle Stan?! Mabel finally had a good look at Gideon' s clothes: blue vest, baby blue hat, orange shirt... Her head spun. The missing bed, Gideon, Grunkle Stan...

"Is that... Journal Number Three?" Dipper said, and Mabel looked at the maroon book. It was Journal Three!

"What, wait, how, who... What?" Mabel stammered.

"Yeah, it is-here, take it and finally leave me alone!" Gideon yelled, his face turning bright pink. Mabel could see his eyes were getting teary.

"Where are we?" Dipper said. He muttered, "This can't be Gravity Falls... Something's up."

"Reverse Falls...?" Gideon said. Suddenly, his face reddened and he balled up his fists. "Wait a minute, you're not Them! Give me that-" He snatched the Journal away from Dipper' s hands. "You better have an explanation for why you're here, in my room, lookin' like clones of me an' Pacifica-"

"Paci-" Mabel started, but was cut off.

"-why you tried killing me, how you got here, and just how you know!" Gideon was breathing hard now, and his face was full blown red. As in red-red red.

Suddenly Mabel remembered.

"The mirror!"

Gideon's rage was now directed at her. "The what?"

Dipper gasped too and stepped back.

"Oh my gosh, Mabel, quest be in some kind of alternate universe! Reverse Falls is the reverse of Gravity Falls. The mirror must've been some kind of interdimensional portal that mirrored everyone; everything's equal yet opposite! That must mean the multiverse theory is true! Parallel universes-"

"Bro, you lost me."

"Basically we're in the opposite of Gravity Falls."

"Oh."

Stunned, Gideon looked at the twins in astonishment. His face went from epic-explosion red to cutie-patootie pink. "Wait, you two know about the weird occurrences that happen 'round here, too?"

"Well in Gravity Falls, yeah, but I bet some things some things are still the same," Dipper said and stuck out his hand. "I'm Dipper and this is my sister-"

"-Alpha sister!" Mabel interjected.

Dipper blushed. "-Mabel Pines. My 'alpha' sis likes to eat toothpaste."

"It's sparkly!" Mabel said with a huge grin and jazz hands.

Gideon frowned. "Pines? So we're, um, related?" He gave them a weird look.

Mabel tried not to gag as Dipper's hand dropped to his side.

"Uh... Let's avoid that topic for now..." he said uncomfortably.

There was a few moments where no one said anything and everyone was thinking the same thing. I'm related to him?! Mabel thought.

Dipper cleared his throat and pulled out his Journal. "Hey, wanna check out my Journal?" he said, breaking the awkward silence.

"You have one too? Do you think it has the same things as mine?"

"Maybe. Oh, and you wanna know how I found it? Well, this guy Norman..." They both walked away talking about gnomes, secret codes, and other dorky stuff.

Mabel watched them go. "I wonder where Grenda and Candy are..." she said, suddenly feeling alone.

In between the time period of lunch and dinner, Dipper tossed his cookies a bazillion times. And, coincidently, it was usually when Stan was asking him the questions.

Mabel, on the other hand, walked around the house, wondered where Waddles was, and frequently answered Gideon's Stan's questions.

"So you're friends with Gids'?" Grunkle Stan asked her and Dipper when they saw him watching t.v. She sat down to watch with him. Dipper walked away with Gideon, leaving her to answer all of the questions. So many questions.

"Yeah."

"Didn't he tell you about all the crazy conspiracies?"

"Yeah."

"Yet you don't think he's some yahoo?"

"Yeah."

"Are you and Dipper twins?" he asked for the millionth time.

"Yes." Mabel sighed.

"You new here?"

"Yes."

At least at dinner, Dipper was the one being interrogated.

Grunkle Stan avoided eating his food and kept on glancing between Gideon and Dipper.

"You two doing cosplay or whatever? Dress up?"

Dipper' s face suddenly turned green. "Gotta go... Mf..." He ran off and somehow got away with the lame excuse. Grunkle Stan looked at Mabel again.

"You two twins?"

Mabel groaned. She really needed to find Waddles, Soos, or someone else sane.