After being set free Bill regained all of his powers. Time Baby was clearly impressed with how much the demon had changed thanks to Mabel's influence when he granted him his freedom. The twins, however, didn't let him off the hook so easily. Dipper demanded he paid him back the ninety dollars he stole from him to buy Mabel's gift, and his sister, remembering Bill's promise to allow her to punish him any way she liked if he ever deceived her somehow, forced him to model the clothes she made for the Admissions Committee. He spent so much time wearing the outfits as Mabel fitted them and got so many needles accidentally stuck on him he was starting to lose it. And he would've lost his mind in an instant if it weren't for his girlfriend kissing his 'boo-boos', as she called them. He hated to admit it, but he really liked that.

Two and a half months later came the day they both loved and hated at the same time: the last day of summer, AKA their birthday. At the end of the day they would return home to start their studies and head their separate ways. It was upsetting, both the splitting up and leaving Gravity Falls, but they knew there was no avoiding it.

As soon as they woke up and entered the kitchen they were surprised by Stan, Ford and Soos, who had all prepared them a party to celebrate their eighteenth birthday and to say goodbye to the twins. They had plenty of presents, a surprisingly large cake, considering how stingy and stubborn Stan was, and all their friends were there. Well, Mabel's friends were there. Grenda spent the whole time stuffing her face with cake and other snacks, Candy was showing off her new robot boyfriend, which clearly needed some repairs, and Pacifica and Dipper spent half of the party awkwardly avoiding each other, and the other half catching up. Mabel had no idea when they had begun talking, but she was happy they did.

Mabel was a bit sad she didn't see Bill all day. She knew he couldn't show himself when Ford was in the room, but she missed his company. She was surprised Dipper and her had managed to hide Bill in the attic for such a long time without Ford finding out.

The party ended not long after lunch time, and as the two older men and Soos were left with the arduous task of cleaning up, the twins headed upstairs to pack their bags, which they did slowly and unwillingly.

"I can't believe we have to go back home already." Mabel groaned, flopping onto her bed. "Summer went by too quickly."

"Doesn't it always?" Dipper sighed as he folded up one of his shirts. "I know it sucks that we have to leave already, but we have no other choice. Our classes start next week."

Mabel blew a raspberry in annoyance. Sure, she was excited to start college, even though she still had to present her creations to the Admissions Committee, but she wished she had more time to stay in Gravity Falls. Especially now that she and Bill were in a relationship.

"By the way, where's Bill?" she asked, propping herself up on her elbows. "I haven't seen him all day."

"Beats me, I haven't seen him either. And I'd think he'd like to see you off."

"Maybe he's… busy?"

"With what? He told Time Baby he'd never go back to his evil demonic ways, which I think gives him a whole lot of free time."

The brunet's phone buzzed in his pocket, his eyes widening when he pulled it out and looked at the screen.

"I, uh… I have to go… do something." He stammered, his face reddening as he made his way towards the door. "I'll be right back."

Mabel watched dully as her brother left the room, forcing herself off the bed to continue packing. Dipper was almost done, but she still had to pack all of her clothes.

She lazily walked up to the set of drawers and opened the top one, jumping back with a yelp when a generous amount of confetti and streamers exploded onto her face.

"Surprise!" Bill exclaimed as he jumped out from inside the drawers, blowing a party horn as he floated in midair. "Happy birthday! Mazel tov!"

"Oh, Bill! You shouldn't have!" Mabel said as she pulled some streamers out of her hair.

"Oh, but I did!" he stated as he lowered himself onto the floor. "I couldn't show up at your party because Sixer and his idiot brother were there, so I had to make it up to you somehow."

"You're the best!" Mabel grinned, hugging the demon tightly.

"No, you're the best, birthday girl!" Bill remarked as he returned the hug. "So, eighteen, eh? You've finally reached legal age. You know what that means." He smirked slyly and wiggled his eyebrows.

"Bill!" Mabel looked up at him with an irritated expression, her cheeks a bright shade of pink.

"Kidding!" He chuckled and narrowed his eyes. "Or am I?"

"Stop!" she giggled, playfully shoving him.

"Fine, fine…" his glanced drifted towards the open suitcase by her bed. "Need help packing?"

"Please."

Bill snapped his fingers and every single piece of clothing Mabel had in the room flew into her suitcase, neatly folded and fitted into bag so it wouldn't take up any unnecessary room. Once all her clothes were in there, the suitcase closed itself and turned over so she could easily pick it up.

"Thanks. I really didn't want to do it myself." She sighed sadly as she sat down on her bed. "I hate that I have to leave."

"I hate it too, but you don't have a choice, do you?" Bill said as he took a seat next to her.

"No… But what about you?"

"What about me?"

"If I'm leaving, that means I won't be seeing you anymore." She whimpered, resting her head on her hands. "I don't want that."

"That doesn't necessarily have to happen."

"What do you mean?"

"Well, now that I have all of my powers back and a butt-load of free time in my handsome human hands…" he pretended to inspect his nails as he explained himself. "…I've decided to go back with you."

"You want to come back home with me?" Mabel gasped and sat up straight.

"And then to your college dorm." He added with a bright grin.

Mabel squealed and hugged him even tighter than before, the demon cringing when he felt his ribs crack.

"Wait, how are you gonna hide away from everyone?" Mabel inquired, raising her head to meet his gaze.

"Hey, you and your brother managed to hide me in this crummy attic all summer." He gestured around the room to emphasize his point. "Plus I can just hang out in the mindscape while you're busy."

"OK, but how do I call you when I want to see you? Do I say your name three times or something?"

"No, I'm not Beetlejuice. Although I did hang out with him once. He's a really fun guy." He chuckled to himself. "Don't worry, I'll know when you're alone. I see everything, remember?"

"How could I forget?" she giggled as she stood up. "Well, I should start taking my luggage downstairs."

"Already?" he whined with a pout. "But I haven't even given you your present yet!"

"Bill, you didn't have to get me anything! You already gave me a sewing machine."

"I gave you that to surprise you when we started dating. This…" he snapped his fingers and a wrapped box appeared in his hands, which he handed to her. "…is to congratulate you for becoming one year older."

"Well, you still didn't have to get me anything."

She took the present from his hands and proceeded to unwrap it. Under the wrapping paper was a package that was roughly the size of a shoebox. She took the lid off of it and a gasp escaped her lips. She took out what was inside the box: a yellow sweater with a brick pattern around it. The fabric seemed to glow a golden hue. It was absolutely gorgeous.

"It's beautiful! Where did you get it?" she asked as she held the sweater in front of her.

"I made it." Bill declared with a proud expression.

"I love it!" she said as she slipped it on over her rainbow tank top, twirling around when she was done. "How do I look?"

"Stunning, as always." He whispered into her ear as he hugged from behind.

She turned herself around and returned his embrace, burying her face in his chest. He rested his chin atop her head, taking in the sweet scent of her hair. He inhaled deeply and exhaled contentedly.

"What?" she asked without moving from her spot.

"You smell nice." He declared with a sigh.

"That's weird!" She giggled, playfully pushing him away. She picked up her backpack and swung it over her shoulders, afterwards picking up her suitcase. "I guess I'll see you at home?"

"Sure thing. I might even join you on the bus, if I feel like it."

She shot him a smile and gave him a quick peck on the lips before making her way out of the room. She sighed happily as she walked down the stairs, thinking about Bill's promise to join her when she returned home and when she started college. She couldn't wait to spend time with him. She wished he didn't have to hide away and only show up when he was sure she was alone, but she knew that was the right thing to do. What would her parents say if they ever found out their daughter was dating a demon?

She heard a ruckus coming from inside the kitchen. Stan and Ford were arguing again about who-knows-what and Soos was trying to calm the two old men down, clearly failing miserably. She decided to ignore them for the time being, crossing the living room and the gift shop until she was outside.

She stood on the porch as she observed her surroundings. Stan's car was outside, waiting to drive the twins to the bus station, but there was no one else there. Since she had managed to pack quickly, all thanks to Bill, Stan and Ford wouldn't be coming out for another few minutes, but she was surprised Dipper wasn't there waiting for her. Come to think of it, he never did mention where he was going. So where was he?

Her thoughts were interrupted when a piece of paper fell at her feet from above. She immediately looked up and saw Bill waving at her from the attic window. She smiled up at him and knelt down to pick up the paper he had dropped, reading what her boyfriend had written in his sloppy handwriting.

Check Sixer's room. ;)

-Bill

She looked up again, mouthing the words 'thank you' to the blond before reentering the Shack. She headed towards the room where she and Dipper had discovered the electron carpet, which had become Ford's room when he returned from the portal. She was surprised to see the door was slightly ajar, since Ford would always close it. She gently pulled it forward, just enough to peek inside, her eyes instantly widening when she saw what was happening in there: Dipper was inside with Pacifica, the two sitting on the couch and engaged in quite an intense make out session.

Mabel's initial surprise was quickly replaced with joy, having to repress her laughter. She couldn't avoid snorting as she pressed her hands against her mouth, which caused the smooching couple to open their eyes and turn their heads towards her in shock.

"M-Mabel?!" Dipper's voice cracked humorously in embarrassment, both his and Pacifica's cheeks bright red. "How long have you been there?"

"Long enough." She smirked, crossing her arms in front of her chest. "If you two lovebirds are done sucking face, I think Sir Dippingsauce needs to finish packing."

She heard Dipper groan as she turned around and walked away, giggling giddily to herself.

Stan, Ford and Soos walked outside just a few seconds after Mabel did, the two old men clearly still annoyed at each other. Dipper was the last one to exit, shooting his sister a menacing glare, glare which she couldn't take seriously with the lipstick stains he had all over his face. There was no sign of Pacifica, which led her to believe that the blonde had exited through the back door.

"What's up with your face?" Stan inquired as he pointed at the brunet's face.

Dipper cocked a brow at his great-uncle and turned around to see his reflection on his car's windows, which made his face turn beet-red.

"NOTHING!" he quickly yelled, his voice cracking again, and proceeded to grab the hem of his shirt to wipe his face.

The twins said their goodbyes, saddened to be leaving their favorite place on Earth. Stan promised to try and convince their parents to allow them back next year, but they both doubted it. Ford gave Dipper one his books on supernatural research to help him with his studies, which the boy gladly accepted. They set their luggage on the trunk of Stan's car and gave each of the three men a hug, both of them on the verge of tears.

"Hey now, don't be like that." Ford said as he rubbed Mabel's shoulder reassuringly. "There's still a chance you might come back next year."

"Yeah, and maybe then you'll get to meet Ash." Soos added, which caused everyone to stare at him confusedly.

"Who's Ash?" Dipper asked.

"Oh right, I never told you!" he chuckled as he slapped his forehead. "Melody's pregnant."

"WHAT?!" Mabel squealed, a wide smile across her face. "You're having a baby? I can't believe you didn't tell me that!"

"Yeah, congrats Soos!" Dipper patted his Hispanic friend on the back.

"Thanks, dudes." Soos blushed and scratched the back of his head. "We just found out it's a boy. And Melody agreed to let me name him after my favorite videogame character!"

"I just hope you're not thinking about asking for a raise, now that you're getting an extra mouth to feed." Stan warned him, looking rather irritated.

Mabel giggled as she pulled off her backpack and turned around to drop it into the trunk. Ford was smiling at the joy of his brother's employee, but his smile quickly dropped when his gaze fell upon Mabel's back. Dipper noticed how quickly Ford's mood changed and followed his gaze, his eyes widening at what he saw.

"Mabel!" Ford shouted, causing the brunette to jump in surprise. "What is the meaning of this?!"

"The meaning of what?" Mabel panted from the scare, her heart thumping against her chest.

"Your sweater!" Ford pointed at the yellow piece of clothing as he took a step forward. "Where did you get it?"

"What's wrong with it?" she looked down at herself, not seeing anything wrong with the sweater.

"The back." Dipper whispered to his sister, feeling a bit nervous himself.

Mabel cocked a brow at her brother and pulled the sweater over her head. She gasped when she saw what was on the back, understanding why Ford looked so mad: sown onto the back with black thread was a drawing of Bill's triangular form. She couldn't believe he had given her something that could blow his cover so easily. Maybe he wasn't expecting Ford to see it, but still. What was he thinking?

She slowly raised her head to look up at her angry great-uncle, giggling nervously as her cheeks flushed red.

"I think you have some explaining to do, young lady." Ford stated as he crossed his arms. "And that goes for you too, Dipper."

The twins sighed in unison. Now they really were done for.

AUTHOR'S NOTE (PLEASE READ)

And that's how the cookie crumbles. x)

That's the end, folks! I'd like to thank all those who followed, favorited and reviewed this story and stuck with it every step of the way. When I first started writing this, I never thought it would be so successful. I mean… wow! I really have no idea what to say… Thank you. Thank you all so much. :')

I'd also like to thank all the people who contributed with suggestions. Oh, and before I forget, the bit with Mabel's sweater was suggested by Komnenid. Thanks again, dude! ;)

Thank you all again for everything. I you would like, I am planning to start writing the sequel to this story soon. It's gonna be a bit of a wild ride, so I advise those who are weak of heart to think twice about reading it. Oh, who am I kidding? Nobody's gonna believe me on that. xD

Anyway, I hope you enjoyed this story, don't forget to leave your final reviews before you go, I really appreciate it, and stay tuned for the continuation. See you all next time! ;D

*brofist*

~LeelaSmall