So, this was written a long time ago and has been posted on my Tumblr for a while, and this is the first chance I've gotten to actually posting it anywhere. I hope everyone is having a safe and happy Halloween!

This is a Transcendence AU fic, and if you want to know more about the AU, check out their blog at transcendence-au on tumblr!

Disclaimer: I do not own Gravity Falls

First Halloween

The first year is always the hardest. Transcendence AU

October first was never too early to start planning Halloween costumes. In fact, in the realm of the Pines family, October first was a late start to Halloween planning. They always started Halloween costume planning immediately after Summerween, and Summerween costume planning immediately after Halloween.

Dipper popped onto the physical plane on the first because Mabel had yet to summon him in order to discuss this year's plans. Mabel never took this long to make Halloween plans, not even the holiday after the triplets were born. Not that Dipper was going to admit, but he was slightly worried. Not only that, but Dipper had amazing ideas for Halloween costumes this year which would undoubtedly blow anything that Mabel had planned out of the water.

That was, if he could find his wayward twin star.

"Hey Acacia," He asked his eldest niblet, when he had failed to track down his sister. "Do you know where your mom is? I have a great idea for Halloween this year…" Dipper paused though, trailing off at the shocked face that Acacia was giving him.

"Uncle Dipper," Acacia turned from the sink to look at her uncle completely, and Dipper didn't miss the emotions that were clouding her aura. "Don't you remember? Mom–" And it hit him, and color and corporeality drained out of him faster than a blink.

"Right," Dipper said quickly, waving his hands. "Yeah, I remember. Sorry, I didn't mean–"

He felt the pull of a summons, and let himself be pulled way.

October eleventh found Dipper blipping into Hank's house in search of Mabel. He had yet to talk to her about Halloween costumes, and the holiday was twenty days away! They were way behind schedule with costumes, and they hadn't even discussed what costumes they'd be wrangling the niblets into for this year.

Hank wasn't home, though he did run into Vivi.

"Hey Vivi," Dipper remembered this time to pop onto the physical plane (as there were when he forgot to do so before talking to some of the family). "Have you seen my sister? We need to talk about this year's Halloween costumes."

Vivi jumped, nearly dropping the pile of books in her hands and, oh, yeah, that's right, you were supposed to give people warning before you talked, weren't you?

"Sorry," Dipper said, floating around so he was in front of Vivi. "I didn't mean to startle you."

"It's fine Uncle Dipper," Vivi assured him, but she was frowning. "It's just, your sister, she's been–"

And it hit Dipper at once, and before Vivi could finish, Dipper let himself pull back into the dreamscape and blipping away from the house.

October thirtieth found Dipper answering a particularly strong summons that dropped him off over a familiar stitched rug in the Shack.

"There you are Uncle Dipper," Willow was standing on the other side of the circle. She had her hands on her hips and a teasing grin on her face.

"Willow?" Dipper managed to say, flabbergasted.

"It's the day before Halloween!" She threw her hands up in exasperation. "How are we going to be ready to go trick-or-treating tomorrow if you don't even have a costume?!"

"B-But," Dipper tried to protest, because somehow it felt wrong, celebrating their favorite holiday without his twin.

"No buts!" Willow proclaimed, reaching across the circle to drop a witch's hat on Dipper's head. She laughed as it drooped over one of Dipper's eyes. Her uncle scowled, pulling it off and holding it in a tense grip.

"Mom wouldn't have wanted you to spend Halloween alone," Willow said softly.

"I'll be fine," Dipper lied, because he wouldn't be, but he couldn't let any of his niblets know that. "Besides, Halloween is one of my busiest days– I'll be seeing lots of people. How would I be alone?"

"Dealing with cults and teens on stupid dares isn't spending time with people," Willow told her uncle before holding out her hand. "C'mon, half of any candy we get trick-or-treating tomorrow and as much as you can eat at the annual Halloween party for spending tomorrow evening corporeal with us. What do you say?"

Dipper eyed her hand, mulling the deal.

"What about matching costumes?" Dipper said at last, staring guiltily at Willow's hand.

"Only if you want to," Willow laughed.

"All right," Dipper sighed, but took her hand anyways. "You drive a hard bargain, Little Fighter, but you got yourself a deal."

"What can I say?" Willow told her uncle as they shook on it. "I learned from the best."

I hope you enjoyed it! As usual, please read and review!