Star vs the Forces of Gravity

Marco and Star were just returning home from school, planning on getting started on their homework right away so they could have the weekend to goof off in other dimensions when they were greeted by the sight of Marco's parents excitedly jumping up and down in the living room, apparently in celebration. They turned to regard the two teenagers, excitement unabated.

"Kids! Come quick, we've got great news!"

Marco approached cautiously while Star began bouncing with his parents' infectious excitement. His mother held out a letter and Marco took it, studying it carefully before his eyes went wide and he suddenly joined his parents and their elated jumping, leaving Star caught so off guard that she stopped bouncing as the three of them jumped with arms clasped. She picked up the fallen letter and after a quick scan was left with no real explanation.

"Marco, what's so important about this wedding?"

Marco broke away from his parents, slightly out of breath but still smiling widely as he took the letter from Star's hands.

"He's one of my favorite cousins, Star, and for a while we were worried he'd be a bachelor for life. This is some of the best news ever! Pack your bags Star, we're going to Gravity Falls!"

**

Dipper sat beside his twin sister on the bus, doing everything to contain the excitement his sister was unable to repress as she practically vibrated in her seat. His hand went to the wedding invitation tucked inside his vest pocket, still trying to wrap his head around the idea that one of his best friends was getting married. It had only been a couple of years ago that he and Mabel had helped Soos meet Melody and now the two were getting hitched. He couldn't wait to see them again, them and all their other friends from Gravity Falls, the Pines twins hadn't been able to return to the town of oddities since their first summer there.
He idly rubbed the flap of his trapper's hat as he reminisced about the better moments of the summer when his ears pricked up at a conversation two other passengers were having.

"So Marco, do you think your cousin will let me preside over the wedding? I mean they really couldn't do any better than a princess could they? And I've always wanted to give my blessing to a couple, weddings that require the royal family's presence are so rare on Mewny, it's usually funerals after two noble families declare a blood feud or someone getting eaten by hydra while out hunting."

"I don't know Star, I'm not sure if Mewny is officially recognized as a sovereign state or anything, and we wouldn't want to risk invalidating the wedding, it's a pretty big deal to the whole family. If anything went wrong they'd go berserk. Why not let my cousin Soos have his day and just try to have a good time?"

Dipper slowly sat up and peered over the back of his seat, trying not to stare so blatantly as he searched for the owners' of the voices. They were two seats back from him and Mabel, a hispanic boy and a blonde girl in their teens, maybe a year or so younger than himself. The boy was wearing a red hoodie and the girl was in an ensemble of that looked right out of his sister's imagination, including a devil horn hair band and heart shaped marks on her cheeks. The girl, Star, was making noncommittal gestures when Dipper coughed to get their attention.

"Hey, uh, excuse me but did you say your cousin Soos? As in Soos Ramirez?"

The boy, clearly Marco, pulled himself up to get a better view of Dipper. "That's right. Do you know him?"

"Know him?! We helped hook him up with the woman he's marrying! AHHH!" Mabel suddenly exclaimed, unable to hold back her joy as she joined in the conversation, sitting on her knees so she could look over the back of her seat. "Hi, I'm Mable and this is my bro-bro Dipper and oh my gosh I love your outfit!"

Dipper was beginning to wonder if Mable's excitement wasn't at least partially due to a secret stash of Smile-Dip but pushed the thought aside as he focused on the conversation.

"Nice to meet you, I'm Marco Diaz and this is my friend Star Butterfly."

"I'm so excited about all of this, it will be my first Earth wedding!" Star said giddily as she clutched what looked like a toy wand.
Dipper and Mabel exchanged glances at her comment and some of what Dipper had heard earlier made him curious. "So not to change the subject but Star, I couldn't help but overhear that you were from Mewny… where is that by the way?"

"Another dimension," she answered simply before turning to Marco. "I know you said you and your folks were handling the wedding gift but are you sure your cousin wouldn't like a laser puppy or two as well? Your folks love the litter we have at home."

Mabel beat Dipper to the punch as she tilted her head and asked, "What's a laser puppy?"

"I'm glad you asked," Star said even as Marco began to protest. She held up her wand and Mabel and Dipper ducked behind their seats as it began to glow. There was a quick flash of light and then there was a puppy of indeterminate breed running around in the empty seat between the four teenagers. Dipper and Mabel stared in wonder as the puppy ran in circles, occasionally firing laser blasts from its eyes that left slight scorch marks in the seat's upholstery.

"How…?" Dipper started to ask.

"Did I forget to mention I'm a magical princess?" Star said in a playfully coy manner.

Marco and Star both suddenly looked to Dipper in confusion as he plugged his ears, though they quickly understood why as Mabel began to hyperventilate while simultaneously emitting a keening wale of pure joy as a childhood dream unfolded before her. She showed no signs of stopping and the four of them were starting to garner looks of annoyance from the few others passengers as well as the driver. Dipper pulled the ear flaps of his hat tight over his ears, tying them tightly as quickly as he could before diving for his sister's bag under her seat. He grabbed one of the many sweaters kept within and threw it over his sister's head like a sack, using the thick wool she knit it from to dampen her happiness shriek into a barely audible whine that grew softer as Dipper knotted the arms over her head. Marco and Star watched in a mixture of concern and amusement as Dipper waited for her to finally quiet down or pass out, whichever came first. At long last she sagged against the back of her seat and Dipper could faintly hear heavy breathing.

"Mabel, is it safe to let you out of Sweater Town?"

She slowly nodded her head and Dipper undid the woolen restraint, allowing her to pull it the rest of the way off. She took a moment to compose herself once freed, brushing her now frazzled hair with one hand before practically leaping into the empty seat, startling the nearly asleep laser pup.

"Ohmygoshyou'rereallyamagicalprincess?!Tellmeeverything!Howmanyprinceshaveyoudated?Doyouhaveanolderbrother?"

Dipper and Marco shared a look as Mabel's enthusiasm made her nearly unintelligible before Dipper motioned for Marco to join him to spare him from his sister. Marco graciously took the offer and settled in to Mabel's vacated seat.

"So how do you guys know Soos?"

Dipper cast a glance out the window to judge how much farther they had to go before settling into a more comfortable position.
"Well it's kind of a long story."