Despite the dread that sat in his stomach—well, lower abdominal cavity—throughout the morning, nothing happened. There was no threat, no ambush...nothing. To say Sans was having second thoughts was an understatement—he was on his third or fourth thoughts halfway through his shift. Even so, he'd heard too much from others to discount what he was feeling. And, once his lunch hour hit (Asgore was adamant that his guards have breaks), he was off to Hotland to find W.D. Gaster, the Royal Scientist.

As he reached the lab, he couldn't help but be nervous. Despite being a household name, no one knew much about Gaster. He was the Royal Scientist, yes, but he had zero public presence. Sans didn't even know what the man (maybe woman? W.D. could stand for anything.) even looked like. What if he was bothered by the intrusion? Sans hesitated at the door. This was a bad idea. He wasn't even sure that the threat was real; he was going off of what some dumb guards had said and his own unfounded anxiety.

He puffed out a breath. No. He couldn't do this. There was no need to bother the Royal Scientist, who really was probably very busy and probably had, like, eight experiments going on right now. He turned and started to walk away.

Hsst.

Sans stopped at the sound of hydraulics. Slowly, he turned around. The door was open, and in the bright light, a tall, dark figure towered in the doorway, nearly reaching the top.

"Ah, the Judge has paid me a visit."

The voice was hoarse and strange—it seemed as though it struggled with the words—and something at the shadow's midsection fluttered. Sans took a step back, sockets narrowing.

"How...how did you know I was here?" he asked, tense. The shadow laughed.

"I have, er, cameras. For protection," he said. A long, thin arm pointed up. "The light is not good here, but look closely."

Sans looked up, and he relaxed slightly. "Oh, surveillance cameras."

The shadow's head bobbed. "Yes, yes." It stepped back. "Please, come inside." Sans could make out a smile. "It has been a long time since I have seen one of my own kind."

Sans frowned curiously, but followed him inside and took a good look at the scientist before he smiled. "Oh my god, another skeleton!"

Gaster smiled and took Sans' hand to shake. While he was definitely a skeleton, his skull had two large cracks above and below each of his respective eye sockets, and both of his hands—which seemed to be in continuous motion when he spoke—had jagged gaps in his metacarpals. He gave a small laugh as he caught Sans inspecting him.

"Being Royal Scientist is a dangerous job," he said with a shrug, then motioned for Sans to follow him. "I am sure that being Judge has its dangers as well." He looked over his shoulder and smiled down at Sans. "I am surprised we have not met before, considering we have the same, er..." His hands fluttered again, apparently trying to motion the word. Sans smiled.

"The same boss, yeah." He stuck his hands in his pockets. "The language is pretty rough, isn't it?"

Gaster tilted his head. "I do not understand what you mean."

"I mean it's hard to speak. My parents had the same problem when they moved down here."

Gaster shook his head with a wry smile. "It is a curse. However, I do not let it stand in the way of my work." He guided Sans up to the second floor, which seemed to be a mix of lab and library. "Would you like any tea, Judge?"

"Call me Sans. Judge makes me sound a little, uh, intense." He checked his watch. "And I really don't have time; my break'll be over pretty soon."

Gaster nodded, then looked at Sans curiously. "Then I am assuming you have something you wish to discuss?"

Sans was still for a moment. He was in the presence of one of the greatest minds of the Underground; did he really want to bring up a silly déjà vu question? He looked at the ground, then nodded.

"Yeah...yeah, I, uh...I've heard some talk about people...feeling like they've already done, uh, certain things. And that they've forgotten things?" He huffed and rubbed his neck. "God, it sounds stupid when I say it like that. But...y'know, they've felt like they've already, uh, lived through a day. Like déjà vu. I thought it was just a normal thing, but...but I think I got that feeling this morning." He sighed. "That probably doesn't make sense at all."

"No, no! I understand perfectly!" Gaster said eagerly, pressing his long fingertips together. "What precisely were you feeling this morning? Spare no detail!"

Sans blinked. "Uh, well, I woke up and something just felt...off? And so I went and checked on my brother to make sure things were okay with him, and then I started to get ready and...I mean, it felt so much stronger than déjà vu. Like, like I had done all of that before, and that something bad was going to happen when I got to work."

"And what happened when you got to work?" Gaster pressed. Sans shook his head.

"Nothing. I just waited in there, like every other day. No one came."

Gaster nodded. "Good, good," he murmured. "Here, come with me. I think you will understand." He beckoned for Sans to follow him to a chalkboard with strings of odd symbols scrawled across it. Sans frowned.

"Is this code?" he asked, pointing to the symbols. Gaster, grabbing pages of notes from a nearby table, glanced up, then gave a sheepish smile.

"No, no. That is, er, my language. It is not much in use now, so I do not expect you to know it." He shrugged "And it is easier for me to write when I have complicated information to sort through." He chuckled as he looked through the notes. "You are lucky to have grown up down here. You can be understood."

Sans smiled wryly. "Well, I wouldn't call it luck, but I guess it's convenient." He blinked as Gaster shoved papers in front of him.

"I have translated these notes for my apprentice, but she will not mind if you use them now. But I will still say what I can now. You see, I have a theory." Gaster's hands were moving at top speed, moving in time with his words in a strange sort of sign language. "Time as a whole is inherently unstable, but I believe it is even moreso down here. I suspect it is to do with the high concentration of magic. Magic is like...like a liquid." He picked up a beaker of water, holding it up for Sans to see. "See, in the glass it is concentrated and, er, the word for, er..." He let out a frustrated huff, then dipped his finger into the water. "You can do this."

"You can touch it?" Sans suggested.

"Yes, yes, that is it, but more. You can...immerse? Yes, immerse yourself into it. But, when it is out of the container..." He pushed aside some paper and poured the water out on the table. "It spreads. It is not so concentrated. It is still there, but it cannot be felt like it can when it is contained. That is why we were so much weaker when the humans attacked us, but so much stronger down here."

Sans frowned. "This, uh, it's really interesting, but what does this have to do with the déjà vu thing?"

Gaster chuckled. "You do not think like a scientist," he said. "But I will be brief. I believe that time here is affected by the high concentration of magic. It becomes more...more malleable, I think is the correct word. It can be shaped." He pressed his fingers together again. "You see, humans have a strange ability when they are down here that I do not think they have above ground. They are able to do something called 'reset'."

Reset. Now why did that sound so familiar? Sans frowned, mulling it over. "So, um...so like what you do in a video game?"

Gaster blinked, and he tilted his head curiously. "I am not familiar with, ah, 'video game'."

Sans gave a little smile. "They're human things. Sometimes they wind up in the dump," he explained. "But if you want to play the game over, or if you mess up, then you can start over."

Gaster's socket's widened. "Oh! Yes, yes! That is exactly it, Sans!" He turned back to the chalkboard and flipped it around to the clean side, scribbling wildly as he spoke. "You see, humans do not have much in the way of magic. A little, but not nearly the amounts monsters do. But they have significantly more substance—not just their souls, you see, but also their physical bodies. They are static; monsters are not. So, with enough concentration, they are able to...ah, to turn back time, to go back to when they first arrived down here." He stepped back, tapping the chalk to his teeth as he looked at the complicated diagram he had drawn. "I do not know if it is conscious or innate. I have spoken to a few of the humans—before they, ah...before their souls were used—but none of them seemed aware of what they were able to do." He sighed, setting the chalk down. "But perhaps that is for the best. That would only put off their inevitable fate."

Sans studied the chalkboard hard, ignoring Gaster's musings as he tried to make sense of this. So humans could travel through time down here? More than that—they could completely start over. How would that affect the underground? Maybe he had run into a human...no, that couldn't be right. He was sure he would know if he'd encountered a human—he could definitely beat a human. His sockets widened, and he looked up at Gaster.

"What about...what about monsters who want to reset?"

Gaster looked at him strangely for a moment, then stooped to pick up some fallen papers. "You know, you are not the first to ask me this."

Sans tensed. Maybe...maybe the thing that whatever caused this forgetting wasn't human; maybe it was a monster. And maybe it was working with Gaster.

"Who else asked?" he demanded, taking a step toward the other skeleton as he stood up and set the papers down.

Gaster looked up, then held his hands up. "Please turn your eye off. I know what you can do, and I do not enjoy being threatened," he said coolly.

Sans blinked. Oh. He hadn't even known he'd done that. He let out a breath and cooled down. Once he was calm, he muttered, "Sorry."

"It is fine, Sans." Gaster gave him a small smile, then continued. "I have been approached by several other monsters about this subject. I cannot remember exactly who—I suspect it is because of the resets—but I am certain that this conversation has happened many times." He crossed his arms, but his fingers continued to flutter. "I can only assume that whatever worried you this morning is responsible for these resets, and perhaps others have encountered it as well. Perhaps even including myself."

"Maybe we could find them," Sans said quickly, brain whirring. He had a definite lead with Gaster's information; maybe there really was something here worth investigating. "We could...maybe we could find these monsters and compare what we remember. And then we could figure out what this thing is!"

Gaster tapped his fingers against his teeth, looking dubious. "But they would have no way of remembering." He shrugged. "We may not even remember this if there is another reset."

"Then we'll have to think fast and figure out a way to remember," Sans replied firmly as his watch began to beep. He looked down; break was over, he needed to go back to work. He looked down at the pages he still held. "Can I take these with me?"

Gaster waved a spindly hand. "Be my guest." He smiled. "And please, do feel welcome to return. It is nice to find another skeleton."

Sans gave a little smile to the other skeleton, then waved and hurried out of the lab and back to work. Time to figure out what the hell was going on with these resets.