Author's Note:

(I'm so glad that so many people have enjoyed the first chapter of this story! It was just something that I thought up one day - wondering how Sans would feel knowing that the ending that Frisk fought so hard to get was destroyed along with everything else in the world. Just a bitter and sarcastic ghost making Frisk feel guilty for what they've done.

More story updates are coming soon, hopefully for Interstellar, Sensory Overload, and Ghost Adventures. We'll see how exhausted I end up throughout the week now that school's started back up.)

Wh-what...? What happened to me? Where am I?

Upon waking, Frisk found themselves lying in a dark, cozy room, tucked into a bed that felt slightly familiar to them. Their surroundings were calm and relatively quiet, save for the gentle hum of the heating system in the background. Adjusting their tired eyes to the darkness around them, Frisk could make out a few pieces of furniture beside their bed, and a single door across from them that likely led out into a hallway. The entire room was monotone, with varying shades of red and pink making up the color scheme.

It seemed that somehow, the lost child had found their way back into their bedroom in the ruins. Back before they left to begin their murderous rampage. Back when Toriel was still alive and caring for them. It was all like a dream come true, except... was any of this real at all? Had they finally lost it and were now left to wander their fragmented memories for eternity?

Feeling anxious, Frisk hastily scrambled out of bed and practically tripped over themself to get to the door. The hallway outside was as still as the bedroom, and they figured if Toriel really was here, that she would be sitting in her usual reading chair in the living room. Bracing themself for what may lie ahead, Frisk made their way carefully down the hall and past the front entryway, stalling just before they reached the dining room to settle their nervous thoughts before taking that final step into the open room before them. For a moment, they dared not to open their eyes, afraid that Toriel really wouldn't be there, that everything would just fade away and they'd be left floating in darkness once more. But the anticipation was soon too much to bear, and the small child slowly cracked their eyes open to the world around them...

"Hey kiddo, you're up early. Have a bad dream again?"

...Wait, what?

Sitting casually at the dining table, Sans addressed the confused human standing in the hall, resting his head in his hand as he watched them with a single eye. "Toriel's still asleep, but you can chill with me for a bit if you'd like," he continued, smiling warmly at Frisk and motioning to the chair across from him at the table.

Still dazed and disoriented, Frisk managed to shuffle their way over to the offered seat, wiggling themself up into the tall chair. The skeleton chuckled at this, shaking his head lightly. "Who knew boss monsters were all so big, huh? I'll have to see about getting us shorties some normal-sized furniture," he said jokingly, sitting up straight when Frisk managed to sit themself down properly. "So what's up, buddy? Wanna chat 'n chow?"

Frisk remained silent, staring awkwardly down at their lap as they tried to make sense of what was happening. How was Sans even here right now? This wasn't how things were supposed to be, right? Maybe this was just an illusion after all. The extended silence seemed to concern Sans, as he eventually leaned forward and spoke up again. "Are you feelin okay? I can go get Tori if you need her," he asked softly, worry clearly evident in his voice.

Snapping back to the present, Frisk mustered up the strength to smile at their friend, raising a hand dismissively. "N-no, I'm okay. Just... uhm, could I please have a glass of water?" they responded meekly, still avoiding direct eye contact. Sans' smile returned to his face, and he nodded before hopping down from his chair and making his way to the kitchen without another word, leaving Frisk alone with their thoughts for a moment. Letting their smile fall, they resumed their previous train of thought; just where did they end up this time? From what they could recall, Sans had appeared before them and offered "one last chance" - but a chance at what, exactly? If things weren't simply reset once more, then where were they now? They couldn't think of any point where Sans actually entered the ruins himself, not to mention the fact they were still here in the first place. They never spent more than a few hours in Toriel's care at the most, but it almost seemed as if this time around, they were actually living here. Nothing added up, and the more they tried to piece things together, the more abnormalities seemed to pop up. Was this a new timeline entirely...? Sans had said something about getting this "last chance" himself, but how exactly did he do it?

As they were lost in thought, Sans came back into the room, holding a clear glass of water. He walked over to Frisk's side of the table, gently placing the glass down in front of them before taking his place back in his seat. They nodded thanks to him before taking the cold cup into their tiny hands, staring at their reflection for a few seconds before taking a sip. The water was actually pretty refreshing, and they downed half the glass before finally setting it back down on the table. They hadn't realized it before, but it really had been a long time since they had anything to drink. Sans looked pleased, leaning back in his seat and crossing his arms. "You look like you're feelin' a bit better now," he commented, earning a nod from the small child. "That's good. Sorry you've been havin so many nightmares lately, buddy. Lucky Tori and I are still here for ya," he said quietly, and Frisk noticed an odd expression grace his features before quickly reverting back to his default grin.

The room became quiet once more, Frisk occasionally taking another gulp of their water as they both thought of something to talk about. Finally, the young human sighed loudly and looked up into the skeleton's eyes. They just had to ask him. "Sans, are you... do you, uh...," they stuttered, struggling to think of an appropriate way to word the question. It was entirely possible that Sans didn't remember anything at all, and the last thing they wanted was to alert him of time shenanigans by bringing it up. "How is everything?" they decided to ask, hoping he would pick up on what they meant if he truly did remember. Unfortunately, Sans only shrugged.

"Well, things've been alright, I guess. Despite everything, Undyne's proven to be a pretty capable Queen," he began, failing to notice the utter shock on Frisk's face as he talked. "The people really support her, and they've been doing all they can to help her cause, for better or worse. At least everyone's starting to regain a bit of hope - though Alphys still hasn't made any real progress on the disappearances. Oh, that reminds me, she's gonna come visit us this weekend; she seemed pretty excited to see you again-"

"What did you just say...?" Frisk muttered, still unable to believe what they just heard. Undyne... is the Queen? In no timeline did something like this happen... what is going on here?

"Hmm? Oh, I said Alphys was coming over this-"

"Nonono, not that. What you said first... about Undyne," their voice was growing steadily louder, and Sans noticed the panicked look on their face. He leaned in once more, raising a brow.

"Uhh, just that Undyne is doing well as Queen, all things considered. Is something wrong?"

"Of course something is wrong! Why is Undyne the Queen? How did that even happen!?" Frisk cried out, sweat beginning to drip down their forehead. This isn't possible... this just can't be possible!

Now even Sans looked a bit scared, reaching out a hand to try and comfort his friend. "H-hey now, just take it easy! Deep breaths, okay?" he motioned with his other hand, moving it up and down in time with his breathing, trying to demonstrate for Frisk. "That dream must've been pretty nasty, but you're awake now. Just give yourself time to catch up, you'll be back in the swing of things in no time," his voice was gentle and soothing, and Frisk found that they had begun to settle down with their friend's guidance. Gradually, their breathing slowed to an even rhythm, sweat cooling their flushed skin. Right, freaking out isn't going to solve anything...

It appeared that this all was really unfamiliar territory. Sans, too, was different this time around - not only did he fail to remember anything about the previous timeline, but his behavior seemed off somehow; he was more talkative, more personal than before. It wasn't like him to be so tender in times of stress. Usually, the most he'd offer was a bit of friendly advice, with a few awful jokes and rhetorical questions thrown in. What had happened to change him so much?

"S-Sans...," Frisk began, their voice barely above a whisper. Said monster's head perked up a bit, and he leaned in to better hear the child speak. "Could y-you- could you remind me? About what's happened? S-so I can make sense of it all again," they asked, so soft that they had to repeat themselves again before Sans could understand. He removed his boney hand from their shoulder, sitting back in his chair as he recalled the events leading up to their present.

"Well, let's see," he muttered a few inaudible words to himself, filtering through his memories for the more important moments. "You fell on down into the Underground a few months ago. At first, we were all kinda apprehensive about approaching you, but eventually you made yourself quite a few friends on your way to the castle," he winked at Frisk, and they couldn't help but smile back just the same. "Even Undyne warmed up to ya pretty fast. You managed to get all the way up to Asgore, and even though you beat him, you still spared him in the end. He and Tori adopted you as their own, and things were goin pretty well for a while. But," he trailed off then, a darkness washing itself over his face. The atmosphere in the room shifted, a feeling of tension hanging in the air around the two. "Something... unexpected happened. Just like that, a handful of monsters just up and vanished in thin air. Asgore, Mettaton, and... and Papyrus were among the disappearances," his voice wavered, hands instinctively making their way to his chest, gripping the fabric of his jacket absentmindedly. It took a few seconds before he could recompose himself. "Naturally, everyone suspected you. After all, monsters were taught all our lives just how dangerous and cruel humans were supposed to be. They all thought you tricked everyone, made your way into the royal family just so you could destroy us from the inside out. Of course, Toriel wasn't gonna have any of that. She insisted you were innocent, that you couldn't possibly do something so awful. But the people were so angry, so desperate, that they revolted against her. Undyne was the head of this revolution; she just couldn't take the loss of her closest friends, and she blamed it on the Queen for responding so passively. She kicked Toriel out of the castle and banished her to the ruins, taking you with her."

He paused once more, allowing Frisk to process everything they'd been told. What about Flowey...? Didn't he appear at the end of that fight and finish Asgore off? Immediately after that they loaded the save only to fight his Omega form. Another load, and they found the True Lab and fought Asriel. How had this time around been any different? Did Flowey disappear as well? If it wasn't Frisk that did it, then who could have? So many questions were swimming through the human child's head, only to dissipate when Sans picked up the conversation. "Things were pretty hectic, and me being the lazybones I am, I decided to take a little vacation here in the ruins myself. Couldn't just leave the old lady to take care of you all by herself now could I? And since Alphys was an old friend of mine, she agreed to help me out in researching these disappearances in secret. I think that's everything," he finally finished, sighing deeply as relaxed back in the large wooden dining chair. "Did ya get all that, kiddo?"

Frisk nodded, trying to come to terms with this new reality they found themselves in. Everything was so new and awkward, they really had no idea how to approach it. Monsters leave their dust behind when they die, right? So if those that went missing were really dead, their dusted bodies would be left behind as proof. The fact that they simply vanished entirely left a sour taste in the back of the child's throat. Was all their time hopping actually having an adverse effect on others, too? "Thanks, Sans. I've got it all now. I just have one more question for you," they stated, and Sans patiently waited to answer. "Do you think I did it? Do you think I'm the reason they all disappeared?"

The lights flickered.

Frisk flinched in response, afraid that they had angered him by asking such a thing. However, the skeleton didn't seem too phased by it. In fact, as they stared at him longer, they realized that he wasn't moving at all. Nothing around them was moving anymore. Had they said something wrong? Did they mess up?

"Geez kid, you sure worry a lot for a murderous psychopath," a sudden voice behind them made the child jump, falling down from the chair they sat in and landing hard on the floor with a dull thud. The intruder merely laughed, not bothering to help the human up. "Relax, I'm not gonna hurt you. As much as I'd love to, I kinda need you to work with me right now."

Rubbing their bruised head, Frisk looked up at the figure who now stood before them. As they had thought, it was Sans standing there; the Sans they had spoken to in the void, with his bitter smirk and bloody, wrinkled jacket. That familiar red scarf tied haphazardly around his non-existent neck. "What, did you forget about me already? I told ya we'd talk sometime, and I figured I'd come in and do some explaining before you go and screw everything up so soon."

"I told you I got you another chance. Well, this is it. The only timeline left untouched. The only ending you failed to see before you destroyed everything. All I had to do was track it down and stuff you into it at some point, and bingo! We've got ourselves a DIY timeline continuation!" Sans exclaimed, throwing up his arms in mock excitement. "Pretty neat, right? With this, we have some kinda substance to work with. Since the 'game' was supposed to have already ended, everything that happens from here on out is pretty much just a simulation - accurate, but not entirely exact. Still, it should be plenty enough for our end goal," he approached Frisk casually, kneeling down on one knee to reach their eye level. "Do you remember what you have to do? Somewhere in this timeline, there's bound to be something, anything we can use to change things. Some kinda material that'll give us insight on that demon kid, some way we can overpower them. Your presence here has changed a few things; you've noticed, haven't you? Something that shouldn't be possible?"

Flowey. Undyne. The disappearances...

"Get to the bottom of those anomalies, and you'll find what we're looking for. Make the pieces fit together, so the big picture becomes clear. Got it?"

So much was happening all at once; it felt like their head was about ready to burst with so many changes in such a short time. Still, there was one thing they wanted to know...

"Sans, how did you do this?" they asked, surprised that their voice didn't crack.

The bloodied skeleton could only laugh. "Don't worry about that. What's important is what you do from here on. Just try your best to blend in with the setting, and you'll be fine. For the most part," he added, shrugging as he stood back up and turned to walk away from Frisk. "Just try not to do anything stupid."

Before they could respond, Sans had blipped out of existence just as quickly as he'd come, and soon the world began churning and chugging along once more, leaving Frisk left dazed on the floor as everything settled in their mind. They hadn't even noticed they were being talked to until a cold finger poked at their back. The other Sans was moving again, giggling as he grinned down at the human. "You sure you're okay there, buddy? Maybe you should try and get back to sleep," he offered, extending a hand out to help them up off the floor. They accepted graciously, eager to cuddle up under the covers and give themselves some time to think.

"As for your question," he spoke up, reminding them of their interrupted conversation. "No, I don't think you did it. Something's definitely fishy around here, but it's got nothing to do with you. So don't you dare listen to anyone tellin you otherwise, okay?" his eyes looked tired, but he smiled nonetheless. It was nice, having Sans as a friend instead of a dangerous enemy.

"Thank you," was all the child could say before they had been escorted to their bedroom, closing the large door behind them with a soft click.

Maybe this won't be as hard as I thought.

End Note:

(I just love a sarcastic Sans. Also got a pretty neat idea for this lil fic here~

I really didn't expect people to like that chapter so much, but I'm really glad that you do! Undertale is honestly one of the greatest games I've ever played, and I just couldn't resist making some sort of story for it. Any and all reviews are greatly appreciated, as they show me you really liked reading the silly thing I wrote~)

(PS - for those who don't know, school presently sucks motivation out of me like a leech. I do actually have a lot of free time, I just spend that free time doing little to nothing productive because by the end of the day, I'm so tired I don't really feel like doing much else. It's not that I don't want to write, it's just that I have a hard time motivating myself to actually go and do it. I really wish I could just imagine the story and it would just magically appear on the internet exactly how I wanted it so I don't have to go through converting all these jumbled thoughts and ideas into a legible plotline. Or is that just a poor excuse for being lazy...? Hell if I know.)