+Gravity Falls- 3 years later+

"Hey Mabel, I'm going to the library! Wanna come with?" 16 year old Dipper Pines asked his twin sister.

"Sure Dipper! Give me a few minutes to get ready." Mabel told her brother as she grabbed Waddles and ran upstairs to her room.

The twins were back for another fun filled summer in Gravity Falls Oregon. After the whole Weirdmageddon fiasco with Bill Cipher they decided come back every summer to check up on the town. Soos was still the proud owner of the Mystery Shack with the addition that the two Stans still be able to come back and live there. Stanley still loved the place and Ford though it would be convenient for them as a place of rest after their exploration travels. Ford kept all the journals with him and made sure to update them every so often with on their travels.

Dipper on the other hand kept a small field journal with him. It had sketches of the creatures in Gravity Falls as well as some important notes on the side in case of emergencies. Mabel started her fashion business on a website she made with her friends, Grenda and Candy. It was going well for them and the business was on the rate for good demands of her merchandise.

Ford came into the living room and saw his nephew watching Tv. "Hey Dipper, got any plans for today?"

Dipper nodded his head in reply. "Yup, Mabel and I are going to the library today to find some books. I'm looking for some good mystery books today and I'm sure Mabel will be looking for some inspiration for her fashion line." He told his Great Uncle Ford. "Want me to pick up anything for you there?"

The older twin thought as he tapped his chin, "Well there is a book I'm looking for," He pulled out a piece of paper from his pocket with a pen and wrote something down. "Could you see if they have this book for me? It's a rather old book, but they might just have it." Ford handed Dipper the paper with the title name and author on it.

"Sure Great Uncle Ford." After that sentence, Mabel came running down the stairs ready to go. "I'm guessing your ready now?"

"You got that right!" She gave him a thumbs up and started heading for the door. "Library! Library! Library!" She chanted heading out.

Ford and Dipper laughed at her chant, Dipper waved goodbye to his Great Uncle and caught up with Mabel. Walking down the forest path to the town, they waved to some passing creatures such as the gnomes who waved back in return before scurrying off.

When they made it to the Library, the twins ran inside and went to their favored sections. Dipper first decided to find his Great Uncle's book first. He went to the receptionist and asked if there was the book named on the piece of paper.

"That book should be over there in the back Young Pines. Just go past the Fantasy and Fiction section, make a left and go all the way down. The book should be around the end of all those books." The lady receptionist told him kindly.

"Thank you-" he looked at her name tag, "Miss Alice." He went off hearing a 'No problem dear.' As he walked down the directions given to him. The brunet found himself in a dimly lit area of bookshelves. "Least they could do is fix the lightings in this area." He mumbled to himself as he scanned the books. He hummed when he reached the end and found said book. "There it is!" He took out the book from the shelf and tucked it under his arm. "Now I can go find my books." He sighed, but the sound of a book falling behind him scared him a bit. He turned around and found the book that was next to the book he found had fallen. Dipper picked it up and looked it over.

The book is the size of Ford's journal but a black leather cover with a yellow triangle. The belt lock keeping it closed and just waiting for it to be open. That yellow triangle in the middle didn't feel right to Dipper because it reminded him of Bill, but in another way felt familiar. "What is this book?" Being curious he decided to check the book out along with his Great Uncle Ford's book.

"Oh, did this book interest you?" The receptionist, Alice, asked while looking at the book.

Dipper nodded, "I just kinda found it in the back next to the book I was looking for." He told her.

Alice hummed and looked at Dipper. "You can keep book young Pines. This book has always been here, but nobody seems to want to check it out." She handed the two books to Dipper with a smile.

"Wow thank you, but are you sure?" Dipper asked her.

She waved her hand and nodded. "Yeah, I've been managing this library for a long time already. I insist you have it."

"Thanks again Miss Alice." Dipper thanked the elderly lady behind the desk. He went outside and sat on the steps of the library waiting for a hour for his sister. The brunet being curious had pulled out the journal sized book and put it on his lap beginning to unbuckle the lock.

"DIPPER!" The shout surprised him and turned around to find his sister standing behind him grinning. She held three fashion magazines in her hands. "Did you find any good books?"

"Yeah, just one."

She tilted her head confused. Usually her brother would take out more than one book to read. "Just one? You usually take out more than that." She voiced out her thought.

"Yeah, but this one just seemed really weird and peeked my interest." He showed her the book, Mabel showed signs of interest and concern in the book too.

"The triangle on the front kinda reminds me of Bill." She shivered at the mention of the demon triangle.

Dipper nodded and stood up back on his feet. "Let's get back to the shack. We can look inside when we get home."

The two of them headed back towards the Mystery Shack, unaware of the elderly eyes watching them go.

"Children, please fix what you have broken." The person sadly says and goes back to their quiet job.