Chapter Text
Frisk trudged through the glowing blue marshes of Waterfall for what felt like the millionth time, though they knew it was actually the sixty-seventh time, should you count the partial runs where they gave up halfway through. Their well-worn shoes squeaked against the damp cavern floor as they skipped across a file of bridgeseeds blooming over the marshland, known to them by heart already, when the phantom presence at the back of their mind finally decided to stop giving them the silent treatment.
"Greetings, Frisk."
They nearly jumped out of their striped sweater, foot slipping on a damp rock and splashing shin deep into the luminescent water. "Wahh! Jeez, Chara, you startled me! You've been quiet for two whole resets, mate. Where have you been?"
"I have been pondering," Chara said, voice calm and precisely measured, devoid of the exhaustion that clung to Frisk. "Thinking about everything we have seen, heard, read, and everyone we met, which, heavens to Murgatroyd, is a genuinely daunting sum of variables. I apologize for my prolonged absence from our discourse, but I required the quiet to process our current deficit of progress."
Frisk wrung out the damp leg of their shorts and powerwalked toward the next echoing cavern. "It's fine, I'm just glad you're back. So? Mind telling me what you came up with? Did you figure out a way to save him?"
"I believe there is one area we have not explored much of yet," Chara continued, voice carrying a quiet focus. "Pray tell, do you remember what those strange, disappearing fellows said about the CORE and the old Doctor?"
Frisk blinked and dodged a passing Aaron with the bored fluidity of someone who'd done it a hundred times. "You mean those gray vanishy blokes? Hmm... yeah. I remember. He made it, right? And his life got cut short because of his experiments, I think. Anyhoo, what about it?"
"Precisely. The CORE is a geothermal facility, yet its output of magical energy is astronomically disproportionate to the Underground's consumption. It yields enough power to sustain current monster society at least three times over, leaving an absurd surplus. The antiquated power plant of my era was not ideal, its output inadequate. Still, to have a reserve this colossal is either preposterous future-proofing or a concealed secondary function. I believe the good Doctor was channeling this energy into an endeavor to breach the Barrier, and that it is inextricably linked to his disappearance."
Frisk paused by a glowing echo flower, knowing Undyne would show up in the next room. "Okay, I think I get what you're saying, mostly. You're probably right, but what's that gotta do with saving Asriel?"
"I may have a plan," Chara said. "But I will not burden you with details until we are sure of the CORE's true purpose. If my hypothesis holds, we might locate remnant equipment within the CORE's deeper, inaccessible sectors. If we harness even a fraction of that concentrated power into Flowey... well, it could provide the necessary catalyst to reconstruct his original form permanently, independent of the souls. It is magic, the lifeforce of monsters, after all."
Frisk stopped dead, their will flaring up and overtaking the aimless fatigue of the past resets. "Wait. Really? You think we can just blast him with CORE magic and turn him back into Asriel for good?"
"It is a theoretical gamble," Chara cautioned, though eagerness threaded their words. "Yet it poses a higher probability of success than stubbornly resetting without an objective, which, need I remind you, yielded exactly zero dividends and cost us exactly fourteen hours and twenty-two minutes over the past five iterations, if my math adds up correctly."
"Hey, I was trying my best!" Frisk shot back, but a genuine smile was already splitting across their face. "But... yeah, I guess that does make sense. I ain't see no reason not to try. We aren't leaving him behind as a flower."
Renewed direction eclipsed the crushing repetition of previous timelines. Frisk picked up their pace, breezing past Undyne and dodging her spears with practiced muscle memory, tearing through the humid, orange-tinted stretches of Hotland like a force of nature, ignoring scenic distractions and doing the bare minimum to progress, until they finally stood before Mettaton on the stage of the latest "Attack of the Killer Robot," episode, ready to knock his robotic block off. Mettaton launched into his dramatic monologue, rolling cameras and lights ablaze, all pointed on him. Frisk had seen all these theatrics more times than they could count, and so they simply got on with the fight.
The blinding stage lights faded out behind them as Alphys carried away the spent, armless body of Mettaton's EX form. The echo of the encounter dissipated into the heavy metallic hum of the machinery while Frisk spun on their heel and got down to business, marching back into the CORE's labyrinth.
"I must advise the utmost caution moving forward," Chara warned, suddenly, their invisible presence feeling rigid beside Frisk. "The CORE was never intended for unauthorized personnel. Even just the electromagnetic interference from the primary reactor will render your mobile phone utterly incapable of summoning aid should an incident occur."
Frisk waved a hand and kicked a loose bolt across the floor panels. "Jeebus, Chara, no need to sound so gloomy. If something crashes down on us or we tumble into a pit, I'll just reload my SAVE, yeah? Not a big deal."
"Dying is a dreadfully poor and inefficient substitute for prudence, and scarcely a comforting contingency for either of us," Chara sighed, but they did not press the issue as the two of them ventured deeper into the facility.
The environment deteriorated with remarkable enthusiasm the farther they wandered away from the designated pathways. The sleek blue floor plating gave way first to dull industrial panels, then to barely finished catwalks. Bundles of exposed wiring hung from the ceiling grates like dead vines. Various pipes threaded across the walls and ceiling in patterns so complex that they almost resembled a coherent build plan. Every few meters another valve leaked a slow stream of strange, sickly liquid onto the floor, where it pooled in faintly luminous puddles. Tread plated walkways were slick with a persistent layer of oil that dripped steadily from somewhere overhead, forming a delicate but highly inconvenient precipitation cycle, and burned out fixtures left long corridor stretches swallowed by a thick artificial twilight in which the ends of the hallways simply stopped existing in any practical visual sense.
One could, perhaps, describe the atmosphere as mysterious. A more practical observer might have described it as an extremely compelling argument for turning around and leaving immediately. Naturally, Frisk did not. They navigated the gloom for what felt like hours, taking arbitrary lefts and rights, until a deafening metallic groan shook the floor plates beneath their shoes. Grinding sounds of heavy machinery followed as unseen gears locked the layout into a new configuration. The pathway behind them shifted away, a solid wall of steel sliding up to seal their exit, which was honestly something they should have seen coming considering the CORE was notoriously designed to rearrange on a rigid schedule.
Eventually the rerouted corridors deposited them in an isolated block of abandoned administration offices. Desks were buried under mountains of redacted blueprints and censored technical readouts. Some rooms held toppled and most likely broken machinery of various shapes and unknown purposes. They were machines in the same sense that a collapsing star is technically a form of light source. They were heavy, somewhat dented, and all carried the vague, heavy historical implication that someone, somewhen, had used them for a purpose far more complex than a conveniently placed holder for empty coffee mugs. Lab equipment lay strewn across the floor in a haphazard manner, with shattered glass vials and propane burners lying unceremoniously scattered about as if they were carefully preserved evidence at a long forgotten crime scene. All unmistakable signs of this space being utilized as a makeshift field lab once upon a time.
Tucked in the corner of the largest room sat a vintage audio recorder caked up with a layer of dust. When Frisk forcefully jammed the play button, a staticky log began to emit, a voice heavily distorted, compounded by the rustling of the tape, speaking in a strange, almost incomprehensible accent that seemed to echo from several directions at once, documenting a bizarre experiment concerning a darkness which was darker than dark.
In filing cabinets deeper into the administrative wing were probably highly classified files detailing the theoretical process of converting raw magical energy into temporal energy, along with a barrage of advanced physics jargon that flew over both their heads.
"Okay, yeah, I think I got most of that," Frisk lied, scratching the back of their neck as they set the document on a nearby desk. "But where's the thing? You know, the giant funnel that pumps the magic into stuff?"
They spent twenty minutes tearing the room apart, searching behind filing cabinets and prying up loose floorboards for some hidden, massive energy-channeling device, only to realize the grand contraption they had pictured was but a fabrication of hopeful imagination.
"It appears our optimism has outpaced our practical technical expertise," Chara muttered, observing Frisk as they spent solid five minutes peering somewhere behind the scenes, trying to memorize the exact alphanumeric designation of the room they're in, for quicker access later. It had to be done exactly right, lest getting back here wouldn't work, or worse, they'd end up somewhere else completely. "Even I am uncertain what to make of much of this. We require the succour of a competent expert, one who can genuinely comprehend these specifications, let alone fabricate the apparatus required."
Frisk nodded, turning their back on the dark core of the CORE. "Yeah, reckon you're right. We should head back to the Lab and show this to Alphys. If anyone knows how to build a magic funnel thing, it's definitely her."
* * *
The sliding doors of the laboratory parted with a pneumatic wheeze to reveal a small dump of empty instant noodle cups and tangled wires, which culminated in a very startled royal scientist hunched over a bulky computer plastered with sticky notes and action figurines.
Frisk leaned over the cluttered console, ignoring Alphys's frantic attempts to minimize a window. "Heya, Alphys, could you help me with something back in the CORE? We found this weird hidden office and I kinda need you to take a look."
Convincing Dr. Alphys to leave her monitorlit sanctuary was another puzzle altogether. Mostly because she started sweating through her lab coat the second Frisk mentioned the restricted zones.
"U-umm, I really don't think I'm supposed to go up there, Frisk," Alphys stammered, aggressively fiddling with her sleeve. "It's super dangerous, and I-I have a lot of important, uh, stuff to catch up on. I usually monitor those areas remotely anyway! If- if there's anything you need, I can, um, control the sections from here."
"Please, Alphys? I really need your help with something super technical there, and you're the smartest person I know," Frisk pleaded, weaponizing their unwavering optimism to chip away at the nervous scientist's defenses until she reluctantly agreed to at least take a look.
The trek back through the mazeful corridors was painfully slow, but they eventually guided the anxious scientist into the dilapidated restricted block. Once they stood amidst the rusted machinery and toppled desks, Frisk took a deep breath and leaned on the phantom voice in their head to sound even remotely scientific. They paced across rusted floorboards, as they vaguely described their intention without ever mentioning flowers or boss monster essences.
"So, basically, we gotta channel some of the CORE's magic into a determination-infused vessel, yeah? Then use that magic to turn it back into whatever it used to be before it became one," Frisk finished, and as they did Alphys froze, color draining from her already pale scales as her mind connected the dots. She suspected Frisk knew entirely too much about her failed experiments, their unnaturally confident behavior always engendering a sense of someone who has seen everything before, but she forced the panic down and adjusted her glasses.
"That's... no, that's impossible," she countered, the nervous stutter momentarily vanishing beneath her expertise. "Um, I-I mean, even if I could cobble something like that together from parts here, the vessel itself has no structural imprint of the original form, s-so pouring raw energy into it would probably destabilize the matter... and I'd almost certainly mess it up."
"Really? Hmm..." Frisk frowned, crossing their arms. "But what if the vessel did have its original form for a bit, just couldn't hold it long? Like, what if the memory's still in there somewhere, and it just needs enough power to make it stick?"
Alphys considered the hypothetical for a moment, eyes on the floor as her racing thoughts caught up with the magnitude of the suggestion. If the vessel was what, or rather who she suspected it was, and if this worked, it might let her undo one of her worst mistakes, one she now realizes was far more severe than she initially thought. The thought made her quietly, terrifyingly excited, the weight of her insecurities momentarily eclipsed by hopeful possibility.
"I... I think that could... maybe work?" she whispered, then sighed and looked around the room with renewed intensity. "Y-yeah, theoretically, if the pattern's still latent, a big influx of pure magic might help stabilize the molecular degradation." She took a deap breath, before setting her toolbox open onto a relatively clean patch of a nearby desk, the engineering paraphernalia emerging automatically one by one from the fold-out case. "O-okay, I t-think I could make something like that!"
Over the course of the next thirty-six hours, the administrative space mutated into a makeshift workshop. Frisk fetched tools and ice cream from the Lab, sending it through the dimensional box, while Alphys entered a rare and threatening hyperfocused engineering haze. Rusted devices were methodically disassembled, cannibalized, and then reintroduced to existence in configurations their original designers would have almost certainly not agreed with. Exposed conduits were rewired, shattered components soldered back into reluctant functionality. A herd of some large plasma coils, which had previously been enjoying quiet retirement as desk decorations had their purpose reassigned in an abrupt manner. Flickering sparks lit the dusky dimlight and sharp scent of hot metal filled the air as a sprawling tangle of pipes, cables, glass chambers, and housings grew outwardly across the floor like a mecha-fungus. Conduits were spliced directly into the reactor feed lines. Several larger components were bolted straight into the ceiling and floor where natural sciencey interfaces and extensions, apparently a perfectly valid engineering criterion, already existed. By the end of the second day the center of the room was occupied by a towering apparatus, which could only be described as a fusion between a power plant and a blender that had developed scientific ambitions.
"It's done," Alphys panted, scrubbing black grease from her forehead with a claw.
"Wait. Really? You actually did it?! That's amazing! I knew you could do it!" Frisk cheered, staring up at the towering apparatus. "But will it work?"
"I-in theory, yes," Alphys answered, wiping said claw into her lab coat. "B-but we need to bring the, you know, the vessel here immediately so I can monitor output and perform final adjustments. It-it could be incredibly unstable otherwise!"
"Actually... I will need to run it on my own," Frisk said bluntly, stepping between Alphys and the main console and offering a tired, but grateful smile. "It's gonna take a while before I can get the recipient vessel down here, and you won't be around when it happens. Might be safer that way actually."
"Wh-what do you mean, Frisk? I-I can't in good conscience leave you here alone with- um, with such a dangerous machine." Alphys protested, hands wringing as she stared at the contraption. Frisk refused to budge, their will was an impenetrable wall. Reluctantly, she gave in and walked them through the convoluted startup sequence, cursorily noting she'd disabled the magicotemporal converter mechanism in the upper chassis to conduct raw magical energy directly into the primary intake.
"O-okay. B-but please be careful! If it runs for more than five minutes, the ambient heat could get... really dangerous. Maybe bring an ice pack, or um, two. I-I don't want you getting burned because of me." Alphys finished her explanation. "And to protect the vessel from wilting and incinerating away if the procedure fails," She wanted to add, but didn't.
With the machine primed and waiting, they both left the suffocating heat of the CORE and entered the Resort. Alphys scurried toward the L3 elevator with a hundred worried glances over her shoulder, leaving Frisk to step into the elevator leading up onto a quiet monochrome balcony of the capital, and continue the short but familiar trek toward New Home as if this were just another ordinarily normal run.