A small amount of light slowly floods Sans' vision, but the world swirls even as he opens his sockets. He has to shut them again, groaning slightly, and raises a hand to his skull. Pain shoots through it, but he forces himself to sit up regardless.

"what the hell..." he mumbles, wondering if he's hungover. He doesn't remember deciding to go for drinks, though, so that'd be news.

When he finally manages to open his eyes and actually see, his sockets widen in realization. A startled cord pulls at his soul.

"papyrus!" he immediately shouts and climbs to his feet, head whipping around in search of his brother. He feels dread when he sees the target of his search unconcious on the floor not too far for himself.

Sans darts across the lab unusually fast as he goes over to his sibling. He kneels next to the taller body, carefully slipping his right hand below the skull to pillow Papyrus' head. Meanwhile, the left gently shakes him.

"hey, papyrus... you alright?" He tries his best to keep the panic from his voice.

A soft groan can be heard before Papyrus' eye sockets flutter open. He fares better in comparison to Sans' awakening, sitting up as soon as he spots the elder. Relief floods the smaller monster.

"I'M FINE," Papyrus confirms a moment later and surveys his surroundings. Confusion kneads into his expression as he takes in the state of the laboratory. "W-WHAT HAPPENED?"

Everything is a horrible mess. Tables are thrown about, there are cracks in the walls... Some machinery has been smashed or pulled apart. The lights are either off or flickering helplessly, all except for the one right above them, still shining dimly. There's some water or, or oil or some sort of liquid puddled at one end of the room. And right in front of them, there seems to be spots of impenetrable darkness – as if nothing at all exists there.

That seems to be the most unsettling thing out of everything. Sans swallows as he, too, takes note of their surroundings. Papyrus stands and his brother slowly follows his lead.

His eyes fixate onto the machine responsible for all of this. It stands in the middle of those dark spots, looking quite trashed.

"gaster happened," Sans reminds the other reluctantly. Speaking of which, where is that guy...?

Papyrus stills, but it takes a while for Sans to notice. He scrunches his browline as he gauges for further reaction.

"GASTER?" Papyrus starts, and something about his tone alarms Sans already, "WHAT'S... WHAT'S GASTER?"

.

Sans feels out of breath by the time he reaches Asgore's castle. Not from exertion, no. His teleportation is still quite functional. Rather, it's from the panic still swelling in his chest as he fearfully approaches the throne room.

He's taken these few steps for himself, just to collect himself. Gaster is gone. Gaster. Is gone. Gaster. Is. Gone. What is he supposed to do? He's still panicking when he does actually reach the throne room, but at least his breathing is under control.

The skeleton steps inside without further delay. Asgore is talking to another monster, both stood in the middle of that field of yellow. The king immediately hears the doors opening and gets distracted by Sans' entrance.

"Oh!" he starts, interrupting his previous conversation partner, "Howdy, Sans! I wasn't expecting you."

The king and scientist are not particularly close, but it's just like Asgore to remember his citizens' names. Sans ignores that, and the other monster, and pushes farther into the room.

"something has happened," he starts, getting straight to the point. His eyes barely spare a moment to the other visitor, who looks surprised more than annoyed.

Asgore seems to recognize the urgency in Sans' tone and excuses himself from the other citizen. The monster looks between his king and Sans, then nods and hastily exits the throne room. The skeleton doesn't wait any longer than that to speak again.

"th-there was an accident at the lab," he stutters, unexpectedly, and takes another quick breath to try and calm down. "something malfunctioned, big time."

The king looks taken aback, then settles on a serious demeanor.

"Oh dear! Is anyone hurt?"

Sans shakes his head.

"me and my brother were there when it happened, but we're alright. but..." he starts warily, fearing his next comment will heed the exact result he doesn't want, "doctor gaster has vanished."

And just as he fears, Asgore's expression crunches up in confusion, reminiscent of Papyrus' reaction. Sans makes fists inside his hoodie pockets.

"I'm sorry... Who is this Gaster you talk of?"

The short skeleton feels himself deflate, and the disappointment must show in his expression. Asgore is already doting on him.

"There, there! How about we discuss this over a cup of tea? If no one is hurt, we can take things step by step," the king assures with a gentle wave of his hand. Sans shakes his head, sighing. His left hand slips out of his pocket to hold his forehead.

"not again," he mutters to himself, "not this again. damn it."

Asgore takes a chance and strides over, his height easily towering over the tiny monster despite hunching. He places a large, comforting paw onto Sans' shoulder.

"Why don't you walk me through what happened," he suggests, booming voice much softer than one would imagine it goes.

Before he knows it, Sans has brought himself to nod.

Not ten minutes later, him and the king are seated in the latter's house, steaming cups of golden flower tea in front of each. Sans simply stares at his, hands still in his pockets. Asgore cradles his own cup after taking a quick sip.

"Now then..." the king says, moving to gaze at Sans expectantly. He shifts.

"this is goin' to sound really strange," he starts, then pauses to see Asgore's reaction. The boss monster is still perfectly calm, if a little worried. Sans continues: "but you aren't gonna remember things about... anything i tell you about."

Asgore smiles.

"You worry I will not believe you," he deduces, then softly shakes his head. "It is alright, Sans. I will not think you crazy."

He feels a little more at ease after being reaffirmed and, after a moment's hesitation, carries on with his explanation again:

"you had wingdings gaster appointed as your royal scientist a good while back. he was the one to put together the CORE."

Asgore hums at that.

"You're right... I do not remember," he responds, facing the table for a moment or so. Sans nods in acknowledgement. "Why is that?"

Sans breathes in.

"because i'm pretty sure he accidentally erased himself from existence," he explains, frowning deeply as he does. The king blinks in surprise.

"And... That is due to the malfunction you spoke of?"

He's clearly trying to grasp what's going on, and Sans is deliberately slow to continue.

"yeah. there was a machine he was workin' on. it, um. it had to do with our studies regardin' the underground," he tells it as simply as he can. "you remember anything about that?"

"Vaguely," Asgore reports and grasps his chin.

Sans finally gives in to the smell of tea and takes the tiniest sip. He realizes that his hand is shaking and has to put the cup back down.

"okay, well. that's somethin'," he concludes. "you're not the only one to forget about gaster, by the way. papyrus– my brother lost his memory, too. i'm thinkin' no one besides you two can probably remember, either."

A tentative silence follows as both monsters seem to be in problem-solving mode. Asgore is the one to speak first:

"That does sound like a conundrum." He thinks on it a moment longer, then... "Do you think fixing the machine would return things back to how they were?"

Sans wants to laugh, but manages to hold himself back. He humors the thought for a moment, even if wryly.

"the readings i got from the equipment that still works– it's almost like there's a void in spacetime where–" he pauses and shuts his eyes, organizes his thoughts, "it's unheard of." Almost.

"So it is undoable?" Asgore asks heavily. "A shame."

His expression sets into something grimmer. Sans feels guilt where his stomach would be.

"i could try," he then shrugs, though feels uncertain. "it's worth giving it a go."

It's Asgore's turn to nod, but his mood doesn't seem any brighter.

"Come then. Let us finish our tea and go see what the extent of the damage is," the king speaks a moment later and takes another long sip of his drink. Sans can bring himself to do nothing but agree.