AN: Hi guys! So, this is my first ever Undertale fanfiction and I'm super happy with this AU that I've imagined and I hope you guys like it too. I actually wasn't going to post it but I ran it by two of my friends who were pretty encouraging. The response I get will determine if I post any other chapters are not so if you like what I've got going here, please please please let me know! I do want to add a few disclaimers though just in case:

One: My Frisk is a girl. I'm well aware that they're in a sense genderless in the game and I tried really really hard to write this as a gender fluid character but I couldn't get it to work and rather than have it full of mistakes, i decided to make Frisk just a girl. I'm sorry if this upsets anyone. I have nothing against gender fluidity or anything like that. I'm actually a part of the LGBTQ community. Like I said, it was more of a writing style isse.

Two: There will be a bit of an age gap between Frisk and Sans and considering she's still 'underage' that may make some people uncomfortable. If it does, I advise you not to read. There will also be mentions of abuse, alcohol, heavy drugs, violence and possibly rape. If that makes you uncomfortable, please turn back.

Three: Although Sans/Frisk will be the main focused on pairing, other pairings will be mentioned. I'm not sure which ones yet (Papyrus/Mettaton for sure) so just a little heads up there.

okay okay, enough disclaimers, on with the show my darlings!

Chapter One: Somewhere Downtown

The cold was the worst part. Frisk had gotten used to pain that constantly twisted her empty stomach and the burn in her legs from trekking the snow covered streets but nothing had prepared her for the cold. She pulled her thin jacket even closer around her and was thankful that it had finally stopped snowing so her line of vision cleared. Her face had become so numb at times that she had almost considered turning back but it was too late for that. She never wanted to face that house again. She'd rather freeze to death. Her brown eyes stayed fixated on her feet most of the time, glancing up occasionally to look at street signs or landmarks to create a map in her head before returning to the ground. The money she had stolen for a bus ticket had only taken her so far but it was far enough away that she felt safe to walk on foot. She'd been smart enough not to spend all of her coins in one place so she had enough for food, but the money was running out quickly and she was losing hope fast.

A red, hazy glow on the powder white snow caught Frisk's attention and she looked up at the neon sign that caused it. The glowing red letters stood out against the black sky and showered everything around it in a similar tint. The Underground. The girl had never heard of this place before, but she assumed it was some kind of bar or nightclub based on the name. As she stood there debating on whether or not she should go in to warm up for awhile, a cough to the right of her caught her attention and she snapped her head toward the sound as a reaction.
He was beautiful. Mesmerizing even. Frisk could honestly say she'd never seen anything like him before. His raven hair swooped perfectly over one eye, which clearly had contacts in them considering she could see the hot pink color from where she was standing a few feet away. The leather dress he wore hugged his form and only reached the top of his thighs, revealing only a hint of the fishnet stockings beneath. She was must distracted by the fusia high heeled boots he wore that went way past his knees, accenting his long legs and matched the lipstick. His pouty lips were wrapped around the end of a cigarette, the smoke blending in with his breath when he exhaled. She didn't mean to stare but it was hard not to. She was absolutely facinated by him.
"Whats the matter darling?" he asked, pushing himself off the wall with one foot. His cigarette dropped into the snow beside him, the hand that had been holding it finding its home on his hip, "Never seen a man in heels before?"
Her eyes went wide and her lips parted as if she were going to speak but no words came out. Her face was already red from the harsh winds that kept hitting her but she knew she was blushing from the relieving heat that began radiating from her cheeks. She was still searching from something, anything, to say when the man began to step forward. At first, she thought he meant to harm her, but the smile on his face was genuine.
"Don't worry about it. Happens more than you think." He was directly in front of her now and she had to look up just to make eye contact. She hadn't realized how tall he was before, but she was only 5'4 and felt incredibly small next to him. "You got a name sweetheart?"

"Its Frisk," Her voice sounded so foreign to her. She hadn't spoken out loud in a week and the action was rather uncomfortable now. She began to rub at her dry through and cleared it, trying to make herself sound louder. "You?"

"My real name doesn't matter. I haven't used it in so long that its more of a distant memory than anything. Just call me Mettaton. Its great to meet you darling. I'm sure you're rather starstruck." He took her free hand and brushed his cold lips against the back, leaving a small kiss mark. "You seem to be a bit lost, Frisk." Lost? How could she be lost when she didn't even know where she was going? She shook her head.
"Oh, I beg to differ. I can see it in your eyes dearie. I had that look in my eyes once. Let me guess, home is that way isn't it?" He pointed behind them. "How old are you Frisk?"

Frisk held her breath. This was the first time she had to tell this lie and she didn't want to blow it. "Eighteen," she said a bit shakily. "My birthday was last month.." That part wasn't a lie. She'd turned sixteen on January 17th. She couldn't tell if Mettaton believed her or not. He was a hard one to believe. If he thought she was lying, he didn't say so.
"You must be cold darling, and I can hear your stomach from here. Come with me. Let mama Mettaton take care of you."
Frisk was hesitant. This person was a complete stranger and she had no way to repay him. "I can't.. I need to find some place dry to sleep before it gets too late." The sun had just gone down so she was guessing it was close to eight. She hated walking later than ten. Besides, all the good spots were usually taken by then. "And I don't have any money to eat. Thank you though."
"You just found some place dry to sleep. I have a room upstairs. I'm sure I have a change of clothes that will fit you. And as for food, its on the house. You don't really want to be out here any more do you?"
"No.. but why are you being so nice to me. We just met."
Mettaton squatted down so that he was eye level with Frisk, a sad smile on his lips. He brushed a strand of hair out of her eyes, looking at her for a few more minuets before replying with, "Like I said before, dear, I was you once... and I don't want you to end up like me." He stood up and held out his hand, which she happily took and let him lead her inside, taking one last look at the neon sign before the door shut behind her.