A/N: Hello, everyone, my name is clearlonelysky, or CLS to be succinct.

Though I've been a fan from the start, this is my first try on an Undertale fic, due to a sudden inspiration. :D
I sort of have an idea and some drabbles of how this storyline is going to unfold and conclude, but I imagine it will not last too long of chapters. (Edit: *cough* I take that back.)

Anyway, this is a Sans x Frisk fic (which I like to call Sansk) with reader insert in second person. And of course because the reader is Frisk, he or she will be referred as Frisk in the story by other characters. Frisk will not be gender defined, but there might be some bias to what I imagine my version of Frisk to be.

And unfortunately, the story here is pretty dark. There are references to various kinds of hatred present in the human world. Let yourself be warned if it makes you uncomfortable.. I'm aiming for a lot of feels.

So, here we are with the story. Thank you.

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"...what did you say..?"

"...I'm going to reset."

...

"no."

The cold winter wind bit through the silence as did his frigid voice. His alabaster skull was as pale as it could ever be, in dread of losing someone else.

You looked at him intently, eyes holding immense depth of sorrow.

"I have to Sans, it's the only way-" you started with him,

"stop."

"-it's the only way to bring back Papyrus!"

You could tell, that Sans noticeably shook from your forwardness. He looked down, refusing to face you, yet you could not let his quiet plea stir you from crying out your desperation.

You trembled and continued in agony,

"I have to tell them! I have to return and warn everybody not to come out to this god foresaken place..!"

"..."

Listening silently, the skeleton had no words to offer. But you knew the heart of his was already hollow and bottoming itself out.

No words could describe just how much of deep snow you were in with him right now. Not even Snowdin had winter lasting as cold and bitter as this one before...

Right now you were standing alongside the blue fur coated skeleton, in front of his brother's grave. His one and only. Dead leaves and wilting grass were surrounding the lonely tombstone to keepsake his dust remains.

It had been but a month since his tall cheerful younger sibling had passed. By far, you could attest his innocent brother had nothing but pure and hopeful intentions in him, always ceaselessly believing in the universal kindness within humans. But the very world that he used to believe in was not on his side. To everyone's absolute horror, while the vivacious younger skeleton was actively participating in another one of numerous peaceful demonstrations calling for monster rights, his crowd of supporters had been violently raided by human extremists, triggered by the influence of their new rising leader.

And it wasn't just Papyrus that they had lost until then...

Too many innocent souls have been taken since that faithful day out to the surface years ago. The first scenery they had met with their eyes; the beautiful ray of sunrise, promised them with hope for the future, but little did they know reconciliation with humans was an overwhelming task to conquer. The ticking and proceeding of their frozen timeline gravely faced with unpredictable, unmanageable consequences.

No doubt, when they first came out to the surface, humans were fearful than ever at their sudden emergence. And it wasn't long until that fear turned to hatred. Humans had a tendency to hate and discriminate what they did not understand and what was different. So after realizing that monsters could be far weakened from their ill-intent, more and more humans turned to abuse. What with the thick of already embedded hate and prejudice even within their kind, the humans ended up finding the perfect target to vent their hatred—the newcomers from the underground, or as they called them; freaks, demons, filthy creatures... Undergrounders.

Strangely and morbidly, with the discovery of a much more different kind of species, a far more common antagonism was created, as the call for humans to unite and come together became stronger than any other time in existence. Although there had indeed been kind and right-minded humans who spoke for equality and compensation for their lock-up, their opinions were often trampled and met with harsh denunciation. Despite the difficulty, much progress have been made and policies have been ratified for the past many years. But life did not get any easier.

Unspoken or outright discrimination was prevalent. Toriel, your adoptive mother, had accomplished her dreams of becoming a teacher with monumental efforts, but had to face severe ridicule and bigotry in and out of her workplace with minimal protection from the law. Asgore, after the two gradually found mutual comfort, reunited with her and became your father, but could not evade constant interrogation from the human community of whether he should be held responsible for his actions for taking human souls, or be exonerated considering the circumstances that were put on him by the human race in the first place. From all the controversy, he himself was guilted by acknowledging his past acts and his wife blaming and leaving him for his incompetence before. Your parents were going through another marital crisis due to hard times, and though that did not mean they had been negligent to you, you were saddened by the noticeable distance that grew between them in your house.

As for Undyne and Alphys, their obvious feelings for each other could not follow through in the eyes of society. They have worked hard in their best endeavor to overcome discriminatory glances, but at the end, they came to a decision that they should take a break in their relationship, thinking that probably them staying apart for some time was best for both their safety.

And when the two were hit with the unfortunate news of Papyrus, they mourned in their own ways of grievance, staying put in their separate homes. Afterwards, Undyne ultimately took on the path for vengeance, as none of the police force were willing to investigate the incident of her dear guiltless friend. The brave and self-righteous warrior had for many years suppressed her aggressive methods after realizing the backlashes that always inevitably came after. But her last straw of patience had broken. She vowed to get to the bottom of this and serve justice herself. Despite everyone's pleading disapproval, she adamantly converted towards vigilantism and disappeared shortly after the skeleton's death, never heard ever since.

Her lizard partner had been completely out of herself after that, choosing to disconnect herself with any outside contact and instead distracting herself with endless re-runs of animes, junk food, and incessant mumbles to herself that everything was going to be okay. Though you attempted multiple times to persuade her out her distress, the recluse had not once agreed to step out of her shut doors. She had also long let go of her lab work and research, as she was immediately labeled a disgrace and was not trusted for her past unorthodox experiments underground. Her updates and repairing of Mettaton had in due course, come to a stop. The robot had disappeared shortly after that. Some say they have seen an old outdated automaton in the midst of a roaming circus, but the truth of it had not yet been verified.

...You could hardly find any hope in this grim situation. At this stage of grief, the determination you were known for, had almost dissipated with all your energy.

And by now you were feeling pretty worthless in your position of purely 'nominal' ambassador. Looking back, none of your attestments and claims were ever seen valid as you were just a child when all this happened. What's worse, the authorities initially deemed you brainwashed and indoctrinated into their 'savage' ways of living and 'uneducated' culture. As a result, Toriel and Asgore at one point almost lost custody of you for child abuse, if it weren't for their utmost and consistent efforts to prove worthy to take you under their roof.

Your whole school life, naturally, was full of bullying and judgemental stares. Some of those who were at least decent still had no courage to become deeply involved with you in a true friendship, which you have come to accept. You were different from them; it was destined from birth, to be sent down underground to mingle with monsters. But that was another story.

All up to your teenage years, you were a loner with no human to truly call a friend. And while you did not particularly excel in any of the classes, it was a miracle how you got by with most of them.

But all was okay, as long as you knew you could withstand all of it together with your monster companions... Yet, somehow things had gotten worse by every passing year... and every passing sacrifice.

After all this happening, you were now seventeen, close to adulthood, but still incompetent and powerless. You were one human after all.

It was regretful to even call yourself a 'human' by now. What is it that you could do, now that everything came to this?

...Now it all arrived to this confrontation with Sans.

You sighed mentally.

Where to start with him...

Sans in front of you was disheveled, even more so from his usual lazy self, and it was utterly heart wrecking. You remembered, as soon as they came out to the surface that very day, as subtle as it was, there had been hope lighting up in the skeleton. He surely thought, now that they weren't stuck in an endlessly repeating cycle, every one of his efforts and accomplishments would in time come to mean something in the end. You in passing days, have either heard or found out for yourself that this laid-back skeleton had once been an avid scientist, a try-hard, a go-getter, ...until he stepped too far into the truth and grasped the reality of things. His long burnt out motivation, from that point on in front of the sun, seemed to be rising back up to the surface. But to all dismay, after overcoming the one underground, he had to meet with a graver truth above.

Yet, despite all tragic events from the journey, he had insisted, for whatever cost, the free world and free timeline to be better, and better off untouched, compared to the imprisonment before down below. Thus, he had made sure in his hands to both threaten and plead to you to give your word that, once you had set the monsters free, to never ever alter an event or intervene on the decisions of others by reloading or resetting. This, after undergoing his pain countless times from countless events and timelines, you agreed to. In fact, one of them was a trauma to you, as you could never forget how in one of those dimensions, you had let yourself be taken over by the one evil entity and went as far as to hurt everybody... including Sans, the sole one who understood and stayed by you on the concept of time distortion.

So by all means, all this time, no matter what happened, you had done everything in your willpower to stay true to your promise made with Sans, to NEVER RESET.

But now, seeing him like this heavily deterred you from your oath and from a sturdy mind state. He had made himself sentry to his brother's grave ever since, obviously evoking painful memories, so that no one could dare approach and vandalize his resting place even after his passing.

He was kicked out for loitering multiple times, but as of now, the cemetary guard paid no mind in what he did, pitying his situation.

However you for one, weren't about to turn a blind eye, not anymore. Your long hidden determination started to reignite before him.

Sans finally took a sigh, his breath shown in the cold. His harsh dissent relented at what was plainly shown as he shielded his eye sockets with one of his boney hands.

"...kid, do you realize how much you are risking here..?" he shook with his horrors resurfacing, "a reset back to all those years..? your body, it cannot take all of that..." His later sentences fell apart.

"It's better than letting all this ever happen..." You laid down firmly, though barely above a whisper.

Sans couldn't respond for a moment. His hand over his sockets lowered back to his side and retreated to his coat pocket.

"you know it isn't in me to stop you." he said rather curtly, turning away.

It sure pained to see his turned back, though you could understand how it was too much for him.

Tears gathered on the rim of your eyes as you likewise turned to your back. You had made up your mind after a thousand reconsiderations, but it would be an understatement to say that you were scared.

You were terrified... Not for the guarantee of your existence; but for your capability, the end result to your decision, and... the weight of memory.

As you had learned through the past, a memory only remembered by you was a high cost and burden to endure. You might enclose yourself forever in eternal layers of time that only you could recollect. It was what you feared the most, and feared would happen.

..Sans...

You gritted your teeth. It was disgusting.. You knew you were selfish. You knew you were betraying him by making him go through this excruciating experience again...

So you were absolute scum to even hope...that this time, like always, you would still be blessed to have him remember you... even through the immeasurable turn back of time. That's why you chose to tell him this... other than the fact that he deserved to know you were breaking your promise, because he was the one who had even the slightest chance of remembering you...

What if he doesn't...?

You felt yourself still to the bone. He was all you had even out of nothing and evermore. Without him, you...

You took a desperate glimpse over your shoulder to view his rigid back. From all those shared timezones and repeats of recollections, it was obvious that you had developed unrequited feelings for the skeleton for quite a while now. But you have willfully restrained the growing emotions, aware of how it would be viewed, how it would affect Sans as a monster and further drive apart the conflicting community, especially with you as a human child...

A human child viewed as a monster. But regardless... a human, and nothing more but a child.

Who were you kidding... You whipped your head back forward and harshly wiped away your tears with your sleeve. Even if it weren't for that, you knew for sure in no existing timeline in any universe, was it going to be possible.

It was an unfair burden to be put on the already burdened Sans. It was utterly selfish and you knew it.

You took a deep frosty breath. It didn't matter if it broke every bone, or every inch of soul in your sustenance by doing this... You were determined to make things, not right, but for the better. Turn it back to when everything underground was perfectly happy as it was already, and let everybody know how the world they long for is nothing worth looking forward to. Nowhere in the cruel and ill-willed overground had a space of heart great enough to accomodate their eternal kindness.

You sniffled your runny nose from the iciness of the air. It was a formidable task you had taken upon your shoulders. You readied yourself as you closed your eyes, mindfully distancing yourself from the cemetary. A wind of aura disseminated from your spot, from the great amount of determination that was needed. You concentrated harder and harder into the light...

"frisk."

You stopped rigid, the background of black void dissolving instantly. The warmth of coat sleeves and skeletal hands crushed against you and wrapped tightly around your torso, refusing to let go. His jawbone dug into your shoulder, a part of his hitched breathing felt on your cheek. At once at the contact, withheld tears streamed from your eyes.

"...i'll be there waiting, okay?" the skeleton mustered in his breath, his voice a bit shaken and raspy.

"O..okay.. Sans..." You hiccuped through your sobs. You stuffed your face into your palms, overwhelmed with relief.

"...you better remember me, you hear?"

You couldn't help but laugh meekly, "Same goes for you, bonehead..."

There was a low chuckle before you felt him let go. You faced toward him and nodded slowly as a signal for your departure. Your eyes took its last moments of this timeline to search his face, inscribing every inch of the skeleton to your memory. He was in grief, and a wreck, but he was still Sans. His signature fixed smile triggered an ache in your heart at this particular moment in time.

Soon enough, you closed your eyes and let the darkness enfold. Another wind of aura, and the sole yellow ray of long untouched save point appeared before you. You reached towards its immeasurable depth.

"don't disappear on me, kid."

You last heard him say, before you let the intense waves of light take over you.

ㅡ

There was a severe mind-numbing pain spreading all throughout your frame, the world spiraling out of control. You felt yourself plummeting down an endless pit, possibly down what could be a wormhole. But after painfully writhing and stretching yourself out to cope with it, it thankfully alleviated in due time. With that, in quiet blinking, you found yourself on a bed of golden flowers, the scent and sight of it all too familiar.

You pulled yourself up, surprised by how light you felt. You looked down at yourself. What first caught your eye were your tiny hands and noticeably shorter limbs. What was more, you were back into your old striped shirt from all those years ago. To your expected surprise, in spite of your memories intact, you were trapped in your petite younger self.

You wobbled up to your feet, adjusting to your new, albeit previous body. You gave yourself a stretch, all the way down from your toes up to your fingertips. While you were at it, you wiggled all of your fingers that were unquestionably well in place. Then you tried bouncing up and down. All was good, but...

Weird. Something felt amiss, other than your youth-restored body. ...Empty.

At a sudden rush of thought, you gasped as you let your surroundings go dark, in search of your save point light.

Nothing.

...

..

Your legs lost strength to support you, having you land back on the flowers. It was gone. No matter how many times you tried, and how much determination you gathered up like you always did before, there was no light to reach into.

You had lost your ability to RESET.

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A/N: That's what I have for now.

Oh, and if there is anyone worrying about Frisk being a minor, the relationship of Frisk and Sans among depiction of his/her/their minor years are strictly platonic on my part. Which makes me kind of unsure of the rating... because I think the theme is still pretty dark?

Well anyways, I shall return. Let me know of any input.

P.S. the last scene with Sans is inspired by The Girl Who Leapt Through Time.