You've been through shit that someone your age shouldn't have to anymore, so in order to protect yourself, you've been separating yourself from the outside world little by little. Daydreaming, listening to music, reading novels, fan fiction, playing video games are what keep you the most distracted. The last game you played was Undertale, and you read a bit about its alternate universes. You end up inside one of those alternate universes, but you can't remember how you got there. Now, how does it affect your body and soul to be there? Can you save, load and reset like Frisk did? How will you survive? You're not the innocent and cute teenager that makes Sans or Papyrus fall in love with you, like most fan fiction stories depict. You're a woman, almost in her 30's, just divorced from an asshole that used you as a shared sex toy for about 10 years.

(A/N) Hi, everyone! This is my very first fanfic. I've never done anything else, from any other subject at all, but I truly love literature, romance, and Undertale. Plus, I developed a crush on UT Sans, but because I'm projecting a part of myself here, I'm going for the version of Sans that mostly goes with a somewhat mature woman, as far as I can imagine. I already had a story in mind for a long time, but when transferring it to words on a screen, it becomes much harder than I thought, so I'm not good at expressing feelings or having an extended vocabulary. I'll do my best anyways, so please enjoy.

By thw way, this story contains eventual fluff, suggested violence, character death, romance,

Chapter 1: Underfell's Ruins

Summary:

How are you gonna escape this place and not get killed by Toriel?

Darkness surrounds you for a moment, then a peek of yellow catches your eye for a second. When you fully open your eyes, you realize that you're in a cave... A CAVE!

("Wait... I've never been here before, but I must have seen this place... why is it so familiar? ... from internet, or a TV show? maybe... Nah, a video game, perhaps? ... hmm... wait... Undertale was the last one I played.")

When you're paying more attention to your surroundings, you compare this cave you're in with the first place you see when starting to play that mentioned video game. It seems like a perfect real version of it. You've read and heard about so many theories about the whole story, about each place you travel to, and each monster you encounter as well.

("... oh... shit... is this real? ! wait, there's almost no time! If one of my theories is right, then...")

Then suddenly, a golden flower sprouts from the ground, right next to you. It even has a face. You were so excited for a second until you saw it looking torn and hurt, and its face looks so scared and sad, you can't help worrying about it... a lot...

(Y/N): -"Flowey? Are you okay?"

The poor and hurt flower was so shocked by your knowledge on him, that he immediately felt terrified by you. With small tears in his eyes, he asked you:

Flowey: -"H-how do you know my name?! W-what do you want from me?! P-please... d-don't kill me! I beg you!

("shit... I know almost nothing of the alternate universes... for what I've read, this might be Underfell, and if I'm right... this is bad...)

(Y/N): -"Don't worry... I'm not gonna hurt you at all. I can't really tell you yet how I know you, but you'll understand later on... By the way, we should hide, or move fast. Toriel could be here any minute now. She's dangerous, right?"

Still in shock, the little flower was somehow positively surprised when you seem to know about the dangers of the Underground, and felt determined to help you someway.

Flowey: -"If... if you're actually sparing my life, I just wanna say, thank you... so much. And yeah, she comes every day to check on this place. Quickly! Follow the path right away, I'll try to find you a safe place from her!"

You stood up immediately, not caring if your clothes were dirty, and started running towards the only hallway and exit through the giant door. Flowey made you stop just a few times just to quickly show you how the puzzles and the enemies in the Underground work, to find out that you already know how they do. He's feeling each second a little more confident in his hope that you'll be okay, and oddly started to trust you very quickly.

Flowey: -"You're doing amazing... we might be able to escape the ruins without a problem, as long as you're hiding from her. Just a warning, we HAVE to go to her house, because in her basement is the only exit from this place. She might have left the keys around there."

You lifted your eyebrows a little bit and responded sarcastically:

(Y/N): -"Good to know there's a peaceful solution to all of this... by the way, I'm Y/N. Nice to meet you."

Flowey: -"Nice to meet you as well, Y/N. The rule number one in the Underground is Kill or be Killed... I really don't think that anyone in this hell hole can be saved, but avoiding it, though it's as coward as it can get, is a really convenient way to survive"

You start realizing that you're much more athletic than you remembered. You run faster, get much less tired, jump through larger distances, react even faster, your hearing is enhanced, almost like cat reflexes.

Then you find a small room with a pillar in the middle, and some monster candy.

("Nice, I'll take'em all, just in case") You know it's really selfish to do so, but, for all you know, the monsters in this universe are seriously evil, and you WILL need all the help you can get to stay alive. Heck, you're not even sure that you can reset like the main character in the game. You just pray to the gods that both of you will be alive.

Weird thing you see, is a ghost laying down on some leaves on the ground. He looks a little creepy, but also has that sadness you found in Flowey when meeting him. Your curiosity took you to touch him, to see if he'd react in any way, and so he did.

In his defense, he tried to look scary, but instead was surprised to see you calmly smiling and getting closer to him.

(Y/N): -"Hi there, I'm Y/N, nice to meet you"

His shock didn't allow him to get a single word out of his mouth, but you didn't care.

(Y/N): -"You know what's a ghost's favorite fruit?"

The ghost actually started to think if he has any favorite fruit, when in the middle of his thoughts, you said while smiling:

(Y/N): -"It's booberries, silly!"

He slightly shook his head and realized that... you just made a joke... and a pun, at the same time.

?: -Heh... heheheh" and finally smiled back to you. "That was a nice joke... or pun, thanks. I'm sorry for being so rude. My name's Napstablook. It so nice to finally meet someone nice besides all the rude monsters around. Sorry if I scared you. We all have to defend ourselves 'cause everyone wants to kill everyone else. It's chaos, and I don't like that at all."

And from the ground, emerged Flowey looking at both of you with a worried look.

Flowey: -"She's coming this way! hide!"

(Y/N): -"Oh!, sorry Napstablook, gotta go, you should hide as well, Toriel's gonna be here any minute now. Again, it was nice to meet ya, take care, okay?" and you gave him a small wink while running towards a thin and dark hallway to hide.

Napstablook: -"I will, thanks again, bye..." And he disappeared with a sweet smile on his face.

While on that thin hiding spot, you were able to see... her. Very tall, very scary, dust in her worn clothes, a face that tells you she hasn't slept well in ages, or even had a sane thought in ages either... hunger and desperation in her eyes as she walks to the end of a hall, letting go of a backpack she was dragging around.

Your adrenaline levels were so high, that you stopped thinking right and decided to stealthily follow her into her house, not before taking that backpack for yourself. You were almost there anyway, but you wanted to make sure that, if she goes out of her house, the door can be unlocked and you can enter.

You decided to walk at the same time as her, so she can't hear your footsteps, only hers. And it worked. Once she got into the house, she turned around to close the door, and you perfectly hid behind that creepy black tree so she couldn't see you. *Phew*.

Flowey appeared next to you, scared as hell, and freaked out by that "suicidal behavior" of yours, and whispered:

"What are you doing? Do you wanna get killed? I can't be with you all the time to guide you, so please, get your thoughts straight. "

(Y/N): -"Hey, that's a great idea"

You immediately opened the backpack, add some ground dirt in the small front pocked, and told him: "Can you move here? that way you can whisper and I'll hear you, and we can run away from this place together"

The surprised flower opened his eyes and looked at yours with a happy hope he thought he couldn't feel at all. "Really? You'll take me with you?"

(Y/N): -"Of course I will. You're the first friend I have and I care about you, now get in there, you'll be safer and more useful there"

He immediately nodded and took his roots out there to quickly stuff himself in the sturdy pocket of that backpack.

Once you two were done with that task, you heard the door opening again. She left the house and the creepy front yard as fast as she could and went on as you stopped hearing her loud footsteps as she walked further and further away.

You went inside the house confidently and started searching through the whole place.

Y/N): -"Okay... First, left side."

Okaaaaay... boring looking living room, faintly smells like ... rust?... no. Blood... ewww... You follow that stench into the kitchen and find a big and notorious key, next to a pie that looks so nice, but has a red gooey substance inside, which makes you assume that it's where the blood smell comes from, soooo, you move fast from there, and go the right hallway.

"Heh, lucky me." another key was sitting on top of a drawer, next to what you know is a "children's bedroom".

(I know that outside the ruins lies Snowdin Town, and it might be way too cold for me, I need more clothes)

You're only wearing simple "winter" clothes. All black, by the way. A long tight black turtleneck sweater, some black leggings, and black boots. Not good enough, so you entered the bedroom, left the backpack on the bed and went straight to the closet.

You noticed that some really long vines moved around the bedroom. Flowey started checking everything out with a nostalgic and curious look in his eyes.

Flowey: -"Oh my stars, I missed these toys!"

Like a child, he inspected every corner of the room as if he came back from a long trip, happy to be back home.

You tried a few sweaters and jackets until a long black one fit you ( /ybgbzm4d). You also found a puffy red scarf and a pair of gloves. Then sat down to watch the small and cute plant talking to you about a few of his favorite objects in there, then when touching a cute plush goat wearing a green and yellow sweater and brown pants and, he stops. And he starts sobbing.

Flowey: -"Can we take him?"

Y/N): -"Sure, put him in the backpack" Your smile helped him calm down a bit only, as he left the plush in the backpack to keep him company. Then he took back all his vines, and you wore the backpack again.

Ready to leave the place, you almost left the bedroom, when he asked: "Wait, can we take that one too?" A vine pointed to your right. On a cupboard was another plushie that looked like a human with the same clothes as the previous one, but with brown hair, brown eyes, and a happy smile perfectly sewn.

Y/N): -"Go ahead, take him too, but hurry we gotta move now before she comes back".

He took him and then you closed the door and used the keys on the lock that leads to the basement, running down as fast as you could to finally get out of those dark and mournful catacombs.

And just when you could think of your freedom... *thump*... *thump*... *thump*... *thump*... *thump*...

("Oh shit, oh shit, oh shit, oh shit, oh shit, oh shit, oh shit, oh shit, oh shit, oh shiiiiiiiiit!)

Flowey: -"RUN, RUN, RUN, RUN, RUN, RUN, RUN, RUN, RUN, RUN, RUN, RUN, RUN, RUUUUUUUUUUUUUN!"

The hallway starts glowing red as huge fireballs go flying so close to you, in between your legs, right above your head, you'd think it's a miracle that none got to you, but what you see when turning back to look is that Flowey... yes, the fearful flower, is shooting pellets at the fireballs that could actually hurt you, making them disappear automatically and saving you from damage at the same time.

Flowey: -"The door is too heavy so it'll open slowly! If you bump into it, it might open faster so you can get out!"

Y/N): -"How can I close i-" -"It's easy to close it! Go!"

The beastly Goat lady is running in all her 4 paws, increasing her speed to a terrifying level, that you both think you'll die in her mouth instead.

Y/N): -"OH SHIT, OH SHIT, OH SHIT, OH SHIT, OH SHIT, OH SHIT, OH SHIT, OH SHIT, OH SHIIIIIIIIIIIIIITTTT!"

Flowey: -"NOW, Y/N!"