Mabel didn't have to look at the calendar to know what day it was. She could never forget when the anniversary of the Transcendence rolled around, the date etched into her heart as deeply as it was etched into Dipper's gravestone back in Piedmont.

Upon waking up, she let out a soft moan, pulled the thin blanket that she insisted on using even in the dead of summer over her head, and tried to go back to sleep. She was uncertain as to whether the attempt was a successful one, but when she finally gave in and plodded her way out of bed, it was after noon and her mind was filled with the fog of oversleeping. The girl rarely slept so late- on the rare mornings when she wasn't filled with energy, Grunkle Stan usually ended up waking her up for help around the house or in the Library- but today, the extra time spent unconscious was much appreciated. The day was already half over.

Just half a day left, then. Less than twelve hours until a new day dawned. She could handle it.

Dipper, she noted dimly, was nowhere to be seen. Off at a summoning, perhaps, or just off moping in the woods, as he'd done on this day before. A quick peek out the window didn't reveal any mysterious thunderstorms or unnatural gusts of wind- indeed, it was a beautiful day out, calm and still and serene- which was probably a good sign regarding her brother's state of mind. If he wanted to come back and chat with her, then he would of his own accord; until that point, it was probably better for the both of them that she leave him be.

Stan proved eager as ever to get Mabel's help once she pulled herself together enough to give it. The Library was hopping today; a ton of tourists always descended upon the town on the anniversary of the Transcendence, eager to explore the site where it all began, and the Library, filled as it was with tomes appealing to all sorts of paranormal investigators, drew its fair share of attention. Mabel was grateful for the activity, only too happy to keep herself busy hunting down misplaced books or checking out patrons, to do any mundane task that could serve as a distraction. Working made the hours fly by.

But eventually, it reached that point in the evening where Grunkle Stan yelled at the remaining visitors to beat it, and the Library grew empty and cold. As her great-uncle locked up the place, Mabel grabbed the keys, ran over to the rusty, scratched heap of metal that they called the family car, and drove off.

The girl didn't have a destination in mind; she just wanted to be out on the open road, to be away. She rolled down all the car windows, letting the sticky summer air cling to her arms and blow through her hair, and blasted music loud enough to rattle the car as it zoomed down Highway 618; she sang along at first, but her exuberant, off-key singing soon turned to humming, then to silence, taking in the music rather than contributing to it. The mile markers and exit signs all blended together after a while. Mabel had just filled up the gas tank (Grunkle Stan had insisted that she pay for it, claiming that she used it more than he did these days, a claim the girl was skeptical of but willing to go along with) so distance was no concern. She traveled the open road for hours, every so often glancing at the car clock to see whether midnight had arrived or looking over at the passenger seat to make sure that her brother hadn't silently joined her while she wasn't looking.

Mabel was, admittedly, not paying close attention to the speed limit signs she passed. The highway was usually all but deserted this time of night, and given that her primary model for driving experience was Stan, it was a miracle that she wasn't going even faster, given that her great-uncle had been known to break the car's speedometer solely by surpassing its limits. There were a few more cars out and about than normal, but most were heading towards the relative excitement of Gravity Falls rather than away from it, and it was easy enough for Mabel to deftly maneuver around each pair of headlights on her side of the road, passing them and watching as they faded into a mere twinkle in the background, blending in with the star-filled sky above.

It was a car without its headlights on, one still adhering to the overly-restrictive speed limit mandated for the entry ramps well after merging onto the highway, that entered Mabel's field of vision just a moment too late.

On a night that the girl had spent killing time, one that seemed to drag on much too slowly, things suddenly started moving much too fast.

She slammed on the brakes and honked at the dark minivan, but both proved to be meaningless gestures, doing nothing to prevent her car from ramming into the one in front. There was a crash, and the girl could have sworn that she had her seat belt on but the way her body flew up and over the dashboard and through the glass of the windshield indicated otherwise, and in a matter of seconds she had gone from sitting in the driver's seat to lying on damp ground.

Mabel struggled to recall the town names that had been on the latest exit sign she'd passed. How far was she from home, from the nearest hospital, from civilization? Had anybody seen the crash? Would anybody see it, see her, in time to make a difference? She couldn't remember, the markers on the path of her journey still blurred together in her mind.

She redirected her attention to the here and now. It didn't feel like anything was wrong with her legs- she couldn't feel much of anything at all with them, actually- but she was pretty sure they weren't supposed to be quite so bent and twisted. Her head and neck and chest were just a big bundle of pain, her face felt wet and sticky, and a cursory examination revealed that she was covered in blood of an amount she'd only seen once before at a summoning that had gone very, very wrong before she and Dipper could intervene. She had felt wide awake when zooming down the highway, but now, all the girl wanted was to close her eyes and drift into a painless sleep, leaving behind the worrying reality before her.

Carefully, trying to ignore the twinge of pain that came with every movement, Mabel pressed her blood-covered hand to the basic summoning circle that she had inscribed on the bottom of her shoes in black Sharpie.

The symbols lit up as the red melded into the black, before the red turned to gray and she was staring up at her brother's face in a world gone monochrome, her blood mingling with dried bloodstains splattered across his suit.

As they looked at one another, Dipper replaced his suit with shorts and sneakers and a pine tree hat, the very outfit he had worn when working to stop the Transcendence years before. He, who constantly towered over her now (which led to many a heated argument about whether he was really the taller twin or whether his shape-shifting powers meant he was just cheating), shrank down to her size and then kept shrinking until he appeared to be just a child again, young and small and weak, though his eyes retained their inhuman shades of black and yellow.

She waited a moment for him to speak, but he didn't make a sound, just stared at her with wide eyes and slumped shoulders.

"You can fix this, right?"

Mabel looked up at her brother, waiting for a reply but receiving none.

"Dipper..."

Dipper sighed. "I can, but the cost... I wish it could be something else, but it won't work for anything less, it just won't, and I don't want-"

"Bro-bro. I get it. So what's this big scary cost, anyway? Bugs crawling out of my ears forever or something?" She stuck her tongue out, but it didn't lighten up his somber expression.

Dipper broke his gaze, staring instead at what must have been a downright fascinating patch of asphalt. "I'd need to take your soul."

The girl didn't hesitate before responding. "Okay."

"Mabel! You need to take this seriously!"

"I am, bro-bro! But I'm all for being soul twins or whatever."

Her brother closed his eyes and pinched his nose. "It's not- it's not being soul twins. I'd have to own your soul- own everything that makes you you. I could kick you out of your body like- like Bill did to me, or- I could just kill you, or worse-"

"But you wouldn't." Mabel's voice was soft but calm, making a statement as confidently as if she were explaining to a kindergartner that two plus two equals four, and her speech was accompanied by a small grin.

"I... Of course I don't want to hurt you, but you've seen how things can get out of hand sometimes, and... well, I just don't trust myself."

"Dipper."

The boy opened his eyes and let his hand drop to his side, but he returned to staring at that ever-so-interesting patch of asphalt.

"Dipper Pines, you look me in the eye right this instant."

Her brother's gaze snapped up to meet hers.

"I trust you. And I will always trust you. And if you have to take my soul to help me out here, well, I know it'll be in good hands. You got that?"

He nodded weakly.

"Good. Then let's do this."