"Are you sure you wouldn't want me to stay in a hotel?"

"Of course not, Carlos! We will be working late hours into the night, so it will only make sense that you stay somewhere close," said Ford, as he helped bring my extra suitcase into the attic.

"Besides," said Stan, opening the door, "the only hotel in Gravity Falls is disgusting. Not at all like the comfort of the Mystery Shack!" The door swung open, hitting the wall and knocking a rafter loose and onto the floor.

I knit my eyebrows together. Stan shrugged. "It's all part of the charm," he said. I set my belongings on the floor beside the two twin beds on opposite sides of the wall. The attic was modest, smelling of pine wood and... glitter glue? A floorboard creaked behind me. Ford had his hand on the doorknob. "Anything else we can do for you?"

I shook my head. "You've done so much already, thank you."

The twin brothers smiled a bit, and closed the door. I undressed, just a simple pair of jeans, a flannel shirt, and some sneakers. I glanced out the window to look at the beautiful moon surrounded by fir trees. In the window I could see my reflection. I was a tall man, not impressive in build, with dark skin and a mess of hair. I tucked some behind my hair, revealing some gray at my temples. I rubbed the scruff on my chin. I wasn't that old, but this premature gray hair gave me a distinguished look.

I choose the bed to my right and as soon as my head hit the pillow, I feel asleep.

***

"You have glitter in your hair, champ," Stan said.

He was sitting at the table in the kitchen. Ford and Soos were eating bacon and eggs prepared by Soos's grandmother, a lovely old woman who only moved from Stan's yellow chair in front of the television to cook for the family. I wasn't surprised that the shack could house so many people. It was a lot larger on the inside than it appeared.

I shook my head, sending a tidal wave of rainbow glitter to the floor. Soos's grandmother scooted past me with a broom, leaving the floor spotless in her wake.

Soos chuckled. "You must have slept in Mabel's bed, dude."

I cocked my head. "Who is Mabel?"

Stan pulled out his wallet and showed me a picture of him, Soos, and two young kids on a boat. They were a boy and a girl with brown hair, identical twins. The boy seemed less than pleased to be there, but the girl was all smiles and sunshine. I smiled. "Do twins run in the family?"

"It skips a few generations," answered Ford.

"Yeah," added Stan, "So they might have a gang of grandnieces and nephews who'll annoy 'em."

Ford stood up, wiping his mouth on a napkin. "Meet me in the gift shop in a half an hour. I need to collect a few things and we will get started," he said to me.

"But first, breakfast," said Soos's grandmother, placing a stack of pancakes on the table before me. My stomach rumbled in agreement. I dug into the stack, which tasted of buttery, syrupy deliciousness.

"Gracias, señora," I said after a gulp.

"My abuela makes the best pancakes, Science Dude," said Soos through a mouthful of bacon.

"It's Carlos," I said.

"Got it, Science Dude!"

After I had finished, I walked into the gift shop. Light filtered through the screen door and stained glass window, illuminating the Stan-bobble-heads and Mystery Shack snow globes littered on the shelves. A row of blue and white hats with pine trees on them lined a shelf next to the door. They closely resembled that of the hat Wendy was currently wearing. The teenager was leaning back in a chair, her feet kicked up on the counter, reading a magazine. She noticed me.

I pointed at her in a friendly fashion. "Wendy, right?"

She mimicked my motion. "Science Dude, right?"

"Carlos."

She nodded. "Science Dude."

A corner of my mouth turned up in a smile. I guess there was no getting out of that nickname. Suddenly a loud, obnoxious rap song started playing out of nowhere. Wendy pulled her phone out of her pocket and answered the call. "Mabel!"

A loud, excited voice came from the other end, making Wendy hold the receiver away from her ear. Wendy's grunt turned into a laugh. "Okay, okay, give me a second."

Wendy hung up and reached into a bag, pulling out a hand-me-down laptop. She clicked the keyboard a few times and turned the screen toward me. "Wanna meet Dipper and Mabel?"

There was a video chat request from "Pines Family Computer." Wendy clicked 'okay' and the first thing I saw were shiny braces.

Mabel shrieked in delight and pulled her face away from her camera lens so we could see her whole face. She had rosy cheeks and long eyelashes with long, deep brown hair pulled back with a headband. She wore a green sweater with a picture of a raven. I could tell that she and her brother were quite short.

Her brother could have been her masculine double. Well, about as masculine as a young boy could be. They had to be twelve or thirteen at least. His nose was quite red as if he had a cold, with shorter brown hair under a gray ushanka.

"Hello from Mabel-land!" cried Mabel.

"She means California," corrected Dipper.

Wendy leaned in closer to the screen. "I was wondering when you guys would call. Ya know, Dipper, Pacifica has stopped by a few times to ask when you're coming back." Dipper blushes profusely. Mabel whined.

"What about Candy and Grenda?"

"They're planning a 'welcome home party' right now, a couple months in advance," answered Wendy. Mabel slapped her hands to her cheeks in glee.

"Hey guys, meet Science Dude," Wendy announced, turning the screen the full way so that I was in the center of their vision.

"It's actually Carlos, and I'm here as your great uncle's apprentice," I said.

"Whoa, I love your hair!" shouted Mabel, and I blushed.

Dipper perked up. "Wait, you're Ford's apprentice?" I nodded, smiling. Dipper's face was caught between curiosity and... regret?

Mabel poked her brother. "Did you know that Dipper was supposed to be his apprentice?"

I was shocked. This young boy? "Wow, that is amazing!" I paused. "If you don't mind, may I ask-?"

"How I'm qualified?" finished Dipper. He glanced at his sister. "We're smarter than we look. Well, at least I am." He was interrupted with a punch from Mabel.

"We solved a lot of mysteries this summer. How long have you been in Gravity Falls?"

"A few days," I said, furrowing my brow. "Did you say mysteries?"

"Yeah," replied Dipper. "Trust me, you'll know what I'm talking about soon."

"I punched a unicorn in the face!" yelled Mabel, falling backwards from enthusiasm.

I cocked my head in confusion. Wendy laughed and pulled the laptop closer to her. "Yeah, good times. How's high school?"

"Better than expected," said Dipper. "Mabel is taking every art class she can and I'm running for class president!"

"I'm his campaign manager!" said Mabel.

Then a woman's voice shouted from offscreen. Dipper rolled his eyes. "Our mom is telling us to do our homework. Trust me, we CAN'T wait for summer!"

Mabel waved to us, "Tell Grunkle Stan and Ford we miss them!"

The screen went black. Curiously, I turned to Wendy. "What did they mean by mysteries?" My face fell. "Is there a lot of crime here..."

Wendy leveled her hand parallel to the ground and rotated her wrist in a gesture that said "kinda." She started to read her magazine again. "Let's just say there's no reason for the attractions here to be fake."

My mind raced, trying to make connections. A door creaked behind me, making me turn. Ford was standing in the doorway leading into the dining room, rustling around in an old bag. He pulled out a red book, opening it and quickly scribbling down a note. He noticed me and slammed it shut. "Ah, Carlos. Are you ready?"

I hesitated, "Yes... but I have some questions..."

"Good! A scientist always asks questions and searches for answers," said Ford, focusing more on the vending machine next to the door rather than me.

"The twins say hello and they miss you!" called Wendy. Ford glanced back over his shoulder and smiled.

"I can't wait to see them next summer," he muttered fondly. He punched a few buttons on the machine and a loud beep with a puff of steam greeted him. He pulled open the machine to reveal a secret passage. Ford stood proudly next to it. He held out a hand.

"After you."