Well, I finally wrote something! And by something, I mean the first Gravity Falls fanfic I've ever composed. I will update sporadically (a.k.a. whenever I get inspired to write a chapter).

I do not own the amazingness that is Gravity Falls – what do you take me for? Not everybody can ride a buffalo to work…

This takes place during the summer before the twins' junior year of high school.

.::.

Dipper Pines stepped outside and walked to the mailbox. He ran a hand through his messy brown hair as he sorted through the items, not paying much attention as he did so. He shut the door to the house behind him and tossed the mail on the counter. Before he turned away, however, one particular item caught his awareness. He picked up the small postcard, which was addressed to him, and read the message on it. It made little to no sense, and read as such:

C TKKJ EUAX NKRV ZU YURBK YUSK SEYZKXOKY ZNOY YASSKX. EUA GTJ SGHKR GXK OTBOZKJ ZU 618 MUVNKX XUGJ. -MXATQRK LUXJ

His eyebrows furrowed. What the heck…he thought, absentmindedly flipping the postcard over.

He nearly dropped it in shock. "Welcome to Gravity Falls". It had been four years since he and his twin sister spent that amazing, adventure-filled summer in the mysterious Oregon town, and he hadn't thought about it for quite a while now.

Dipper practically ran to his bedroom (he and Mabel no longer shared one now that they were 16) and started digging around for the old, musty-smelling book that was hidden under his bed. He found the seemingly ancient journal and pulled it out carefully, blowing off the dust that had settled on the cover. Dipper couldn't remember when he had last used the journal, but that thought was pushed aside as he turned to the code-breaking page. He recalled the days when he had several ciphers memorized – they were long forgotten after all these years.

He found his Caesar and Atbash code key wheels and examined the postcard carefully, trying the latter code first. After a minute of deciphering, he decided that it had to be one of the 26 different Caesarean codes. He resigned himself to start with the first and work his way through, figuring that he'd find the right one eventually.

By the time he got to the fifth variation, half an hour had passed. A knock came on the door, though it wasn't very necessary, because Mabel opened the door right after she knocked anyway. She was greeted with a sight very reminiscent of the summer before seventh grade: Dipper sitting on his bed with the journal laid out in front of him, papers everywhere, and a code wheel right in the middle. She rolled her eyes.

"Hey, dorkus," she teased, "what conspiracy have you just uncovered? I mean, I haven't seen you pull that old thing out in years!" She gestured to the open journal.

Dipper looked up at his sister. "Mabel, this came in the mail today." He held up the postcard and Mabel's eyes widened.

"What does it say?" she questioned, walking over and flopping down next to Dipper on his bed.

"I don't know yet," he admitted. "It's in code, see?"

"Boo," she replied, making a face. Suddenly, she thought of something. "Hey, what if there's a secret message written in invisible ink?"

Dipper stared at his sister. "Mabel, that's genius! Why didn't I think of that?" He nearly jumped off his bed and started searching for his black light lamp. "Come on, I know it's around here somewhere…Aha! There you are," he said, sitting back down next to his sister with the lamp in his hand and a triumphant look on his face. He turned on the light and shone it on the back of the postcard, immediately revealing handwriting that was all too familiar.

"It says…'Caesar Variation Six'," Dipper read; mentally face palming as soon as the words left his mouth. "Seriously?! I was on variation five when you walked in here!" He sighed. "Well, there's nothing else to do except crack the code."

Painstakingly, he decoded each word, finally ending up with a complete message:

I NEED YOUR HELP TO SOLVE SOME MYSTERIES THIS SUMMER. YOU AND MABEL ARE INVITED TO 618 GOPHER ROAD. -GRUNKLE FORD

The twins stared at the paper for a few seconds in silence. "Sooo…"Mabel finally spoke.

Dipper looked up and slid off the bed. "Looks like we're going to Gravity Falls again."

.::.

A/N: Well, there you have it – the glorious first chapter of my newest story! :P

I love reviews (hint hint), so don't be afraid to give me some!