There was nothing.

Nothing around Sans.

He could deal with that. Could fold back into space, just like he had been practicing all yesterday afternoon.

Except he couldn't. The empty nothingness clung to him. Inescapable. It held him there, suffocatingly tight, wordlessly screaming to him that he was going nowhere, that this was what happened when you tampered with things beyond you.

He struggled. Tried to reach out, back for the plane of space.

But it wasn't there. Space wasn't there!!

No, his silent personification of the emptiness said, and it never will be.

But it had to be! It had to be there! He had to reach it, had to get back! He would never fold space again if he could just get back!!

Sans.

He had to get back!

It's far too late for that.

No, no, he didn't believe that! He could get back into space-

"SANS!!"

Sans sat bolt upright, gasping, almost smashing his face into Gaster's.

Gaster grabbed onto Sans' shoulder, holding on tightly, and Sans leaned into his grip.

Sans looked around a little, and saw the clock on his nightstand. It was seven thirty two, a few minutes later than he and Gaster would normally leave to get to the lab-- normally meaning Sans hadn't been planning on going today. Gaster had decided that he got to take another day off.

"Are you okay?" Gaster asked quietly.

Sans nodded and leaned against Gaster, the taller of the two responding in turn to hug Sans. "y-... yeah. i-... it was just a nightmare."

Gaster chuckled dryly. "I had assumed. I came in to check on you before I left, and you were being difficult about waking up."

"difficult?"

"Yeah. I had to shake you quite a bit. What was it about?"

Sans hesitated, recalling the absolute blackness. "i--... uh... there-... i couldn't fold. i- i got lost outside space, and couldn't fold back in."

Gaster let out a small sigh and hugged Sans again. "Sounds pretty bad. Not too surprising, though, considering."

"... yeah..."

"But you don't have to worry, because you can fold space. You're not going to get lost. Yesterday you went from the clearing all the way home in a single fold. I'm absolutely positive you know what you're doing."

"... yeah. still scary to think about, though."

"Heh. Yeah, I guess it is. And I don't even have experience in being outside space." He stood to leave, then paused. "... You're sure you'll be alright?"

Sans laughed a little. "yeah, i'll be fine. it was just a nightmare. those happen."

"Okay. If you're sure."

"bye, dings."

"Goodbye, Sans. I'll see you later."

Gaster left.

Sans laid in bed for a while after that.

Eventually, he did get up. For a moment, he stood at the door to his room. Then he closed his eyes. Rocked on his toes a little.

Then he took a step through the door, and pulled. There was a moment of that crushing nothing that made Sans flinch a little, and then he was stepping through the door to the kitchen.

Sans blew out a breath and shook himself a little. See? He told himself. Nothing to it. Just fold out, fold in. No getting stuck outside space, or getting lost. I'm fine.

Because he knew Sans' preferences, Gaster kept the refrigerator well-stocked with hotdogs. It was one of these that he had for breakfast. As he ate, he made a decision: today would be the day that he finally cleaned out that old dresser in his room. It had been there since moving in, and he had yet to so much as touch it, all his stuff still sitting in the cardboard boxes it had been brought there in.

So, after finishing the hotdog, he folded back up to his room, and pulled open one of the drawers.

~o0o~

He was still at it when Gaster and Papyrus came home. It appeared that Gaster had no clear designation for those drawers, and had just shoved whatever random crap he had needed to get out of the way into it.

When Sans asked Gaster about this, his suspicions were confirmed. "I just stuffed things in there to get them out of the way. And then I learned the house had a basement, and started shoving stuff in there, instead."

"woah, wait." Sans looked up at Gaster. "the house has a basement?"

Gaster chuckled and nodded. "Yup. The door's out back. I didn't learn about it until I'd been living here almost ten years."

"But..." Papyrus frowned. "Didn't you build the house?"

Gaster laughed. "Annoying Dog, no! I just rounded up some architects and told them, 'build me a house. And make it a good one.'"

"and they just... built you a house? just like that?"

"Of course they did. I'm the Royal Scientist. I would have fired them if they didn't."

Sans scowled up at Gaster. "i'm pretty sure it doesn't work like that, dings."

"I'm pretty sure it does."

"... no, i don't think you can just... fire people. especially if they're not working for you."

Gaster threw his hands up. "They were working for me! I hired them! And also, Sans, I'm the Royal Scientist! I can do whatever the heck I want!"

Sans just shook his head and went back to what he was doing.

After a minute, he looked up again. "hey, what're these?"

Gaster looked at the bundle of cloth in Sans' hands. "Heeeeey, I remember those! Those were my favorite clothes, before I switched to a lab coat."

Sans unfolded the bundle. There was a blue jacket and a deep red scarf. Then Sans turned to Gaster, holding the jacket up in front of him. "... i honestly cannot imagine you wearing this. maybe the scarf, but... not this."

"Well I did. All the time."

Sans said nothing, only going to slip the jacket on over his white teeshirt. Papyrus reached out and grabbed up the scarf, and proceeded to get his arms and head tangled in it. Chuckling, Gaster came to his aid, looping the scarf deftly around Papyrus's neck and throwing the excess back over Papyrus's shoulder.

Then he stepped back, nodding. "It looks good on you. You too, Sans. The jacket suits you."

Papyrus grinned. "Can I keep it?"

"Sure. I'm not going to be needing it anytime soon."

Papyrus let out a happy laugh, and ran over to hug Gaster. "Nyeh-heh!! Thanks, Dad!"

Gaster just grinned and hugged Papyrus back.

~o0o~

A few more weeks passed, and Sans became increasingly adept at folding space. He could make it from his room all the way to the True Lab in a single fold. The nightmares about the empty nothingness persisted for a little while, but quickly tapered off.

Gaster didn't want Sans to tell anyone about his folding ability, though. If people learned what had happened, then they would undoubtedly want to try doing it themselves, to be able to do it too, and then Gaster would get in trouble with Asgore for live-monster experimentation. So Sans kept his newfound power a secret, never folding in populated areas.

Progress at the True Lab continued, as well. Sans could still make folds more quickly and easily than the machine, but progress was coming along.

At one point, Sans had suggested to Gaster that he try to make a fold across the Barrier, but Gaster had been reluctant to let him do so, saying "you've already fallen into things unplanned once, and we just got lucky that there weren't more serious consequences. This time, we'll actually be using the camera."

So Sans kept his folds limited to the Underground.

~o0o~

Sans was taking the day off.

Truth be told, making folds did take a lot of energy, even if it was significantly less than the machine required. But Sans also still had the upkeep requirement on his boosted Magic capacity, and the folds only added to his exhaust. So, every so often, he just took a day off to relax and recuperate.

Today was one of those days.

He was in Waterfall. He liked Waterfall. It was quiet, and peaceful. Well, peaceful most of the time. Waterfall was where Alphys's friend, Undyne, lived. Undyne had no recollection of being in the lab and getting the Determination injections, but that hardly affected the results. Since then, she had become determined to be captain of the Royal Guard. Which meant training. Lots and lots of loud, wild training.

Sans kind of avoided her. She was just a little too rambunctious for him.

But today, he didn't see her.

At the moment, he was sitting on the edge of a bridge. He had taken off his shoes and socks, and had his feet in the luminescent water.  It felt nice. Cool.

And then his phone rang. He recognized Alphys's ringtone. So he pulled the phone out of the pocket of the blue jacket he had taken to wearing around, and answered it.

"heya, al. what's up?"

"S-Sans, where are you?"

"waterfall. why?"

"You're g-gonna wanna hurry over h-here. D-Dr. Gaster says h-he's figured something out!"

"... kay. i'll be there in a sec." He ended the call.

Then he stood up, pulling his socks onto his wet feet, and shoes on over that. Then he glanced around, and, when he saw no one was there, he made a fold.

And then he was stepping through the door of the lab, almost running straight into Alphys.

"Eep!!" She stumbled back. "S-Sans! You s-startled me!"

"heh. sorry, al. what's goin' on."

"I d-don't actually know yet, b-but Dr. G-Gaster t-told me to go get e-everyone." Then she looked over at him. "B-but I thought you w-were in Waterfall."

"i was."

"S-so how'd you get here s-so fast?"

Well. Crap. He hadn't thought about that. "i-..." But Gaster didn't want him telling people about folding space. "uh. i know a shortcut."

Her eyes narrowed a little. Sans thought she was going to ask questions. But she didn't. Instead, she shrugged. "W-well. Okay. I h-have to go find all the s-Spacefold team." She slipped by Sans into the hall.

Just a little while later, everyone was gathered in the Spacefold lab, and Gaster began.

"So. You all remember how I explained folding space when we first began?"

There was a chorus of nods.

"And how I said we were going to get beyond the Barrier like that?"

More nods.

"Well, forget all that. I have some new information, and I was completely wrong."

There were a few surprised murmurs, the ones from Sans and Jeff sarcastically so.

Gaster ignored them, and pulled out a  sheet of paper and a switchblade (where he got the switchblade, no one was really sure, but he had it, and no one was going to ask about it.)

With the switchblade, he cut a circle out of the middle of the paper. Then he laid the paper flat on the table and set the cut-out circle in the hole.

"So, this circle? This is the section of space that is the Underground. And this," he pointed to the small sliver of cut-out empty space between the circle and the rest of the paper, "is the Barrier. It doesn't matter how we fold this space," he picked up the circle and folded it a few times to demonstrate, "we just can't effect anything beyond the Barrier."

For a few minutes, everyone was silent, thinking about that.

Then, Sans spoke up. "okay, so what do we do now, if folding space won't work?"

Gaster looked at the paper, deep in thought. "... I don't know. Yet."

§

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