After Y/N spent the last of her HP healing a little kid's scrape on a nearby playground, she grabbed a candy bar and devoured it. She instantly felt a million times better, but she couldn't shake the sudden feeling that someone was...watching her. As soon as she noticed it, it went away.

At first she was suspicious. Who wouldn't be at the fact that someone you probably didn't know was watching you? But Y/N's thoughts were dragged over to the hole again. For what seemed like the tenth time, she toyed with the prospect of going down, into the Underground. She was usually quick to dismiss the idea, but this time, it lingered.

What if...maybe...

Her heartbeat started to accelerate for seemingly no reason. Excitement and possibility tried to cajole her into doing it. Usually, she tuned them out. This time, her dam was cracking, and a tidal wave of begging and pleading slammed into her unprepared self at full force.

Y/N's subconscious realized that her body was moving, almost as if on its own accord, at a rapid pace towards the valley. She made attempts to stop herself, but it was like her body ignored them and kept going. She showed no change in pace as she throttled down the steep decline. Before she knew it, Y/N had seated herself in front of the hole, staring at it with an intense and almost obsessive gaze.

Thankfully, she gained control over her body again, and growled to herself in anger at her lack of self-control. Y/N stood up and dusted her pants off, right before...

Nobody really knew why it happened, not even Y/N herself. Maybe she tripped on a rock. Maybe the ground was wet. Maybe fate just made it happen.

Well, whatever the case, Y/N slipped and accidentally tumbled into the hole.

~|~

Ugghhhhhhhhhh, Y/N thought, sitting up and opening her eyes. Her head throbbed, and she rubbed it to help dull the pain. Then she actually took in her surroundings.

She bolted to her feet. "What the—" she whisper-yelled aloud.

This was certainly not the surface. Y/N was situated in what looked like a cave, with cavernous ceilings and stone walls. She looked down at what she had landed on. In the middle of the smooth rock floor was a patch of grass that quite a few buttercups grew in. Y/N smiled to herself. At least that hadn't changed.

Her eyes adjusted to the faint light, and she saw a corridor carved into the wall that was shrouded in shadows. Letting her curiosity get the better of her, Y/N crept towards it and started speed-walking through it, eager to get out of her predicament. Little did she know, her adventure was only beginning.

The end of the corridor expanded into a ginormous room that Y/N couldn't see the walls of. A few feet in front of her was another patch of grass, and in it was the largest buttercup she had ever seen.

And it had a face.

Y/N blinked. Okay, this is nuts. I have to be dreaming. I mean, come on. A flower with a face? Even I wouldn't think of something so weird...

The thought only made her more scared. If she wouldn't even think of dreaming it, it meant that it had to be real.

"Howdy!" an obviously fake cheerful voice spoke up. Y/N looked towards the flower, hoping, for once, to be wrong. She wasn't.

The flower continued talking. "I'm Flowey, Flowey the Flower. You must not be from around here."

"Ya think?" Y/N muttered. Flowey ignored her comment and kept going. "So, I'll give you the rundown of how to survive this place. You want to get your LV up, which of course stands for Love. To get it up, you must collect EXP. Here, I'll give you a few levels' worth."

He sent some glowing little orbs of light towards Y/N, and she dodged them. The smile plastered on his smug flower face faded within seconds. (Told you he was fake.)

"Heh." Flowey laughed, but it was out of rage. "You must not have heard me. I said, TAKE THE STUPID EXP!" the flower screamed, and practically threw the balls of light at Y/N, but it didn't take much effort to dodge them easily.

Flowey looked more pissed off than anyone Y/N had ever seen. "WHY AREN'T YOU TAKING IT?! YOU'RE SUPPOSED TO BE TAKING IT!!!!"

"It was obvious that you were being fake and lying to me, so I knew to avoid them," she said simply.

The statement seemed to enrage him far beyond human capacity. He suddenly seemed much more strategic with his glowing spheres, as they began circling around Y/N, closing in on her. She paused, looking at the orbs, and said, "Well, shoot. That's not fair whatsoever."

The flower grinned then, and giggled maniacally. "Down here, kid, it's KILL OR BE KILLED!" he screamed, and brought the orbs in for the final blow.

It never came. A blast of fire burst from behind him, throwing him from her field of vision but probably not killing him. Y/N looked up at her savior, and found herself staring into the kind eyes of a goat lady.

"Well, hello, child," she said softly. Her voice was sweet as chocolate. "What are you doing in the Underground? It is not safe for you here!"

Y/N resigned herself to stay silent, but her E/C eyes were already telling the goat lady the whole story.

"Oh, my child," she said, placing a hand in front of her mouth, "I didn't know that you fell in here by accident. I'm sorry—I should have been more considerate. Please, come with me. I will keep you safe." She took Y/N's hand and led her through a huge doorway and into what looked like an abandoned city.

"My child," the goat lady announced proudly, "welcome to the Ruins."

It didn't take long for the two to get acquainted and fond of each other. They introduced themselves first—the goat lady's name was Toriel—and learned that they had much in common. They both adored puns, liked the color purple, shared a love of buttercups, and most of all, loved the taste of cinnamon butterscotch pie. After a few days, Y/N started calling Toriel 'Mom' (to her delight), because they were so alike and, well, she was like the mother she missed so dearly...

Y/N spent weeks in the Ruins, being happy, eating cinnamon butterscotch pie, and learning about monsters from Mom. Of course, Y/N had heard of monsters, like everyone else. However, her biological mother had raised her to believe that there was good in all things, including monsters, and that they were not to be feared; instead, they were to be loved.

Eventually, Y/N found the courage to tentatively ask, "Mom? Is there more to the Underground than the Ruins?"

Toriel looked upon her sweet child, then sighed, and said, "I knew that you would ask me that question one day. Though I must say, you outlasted everyone else in your patience with that around you."

"What?" Y/N questioned, quite confused. Toriel shook her head. "Never mind. If you must see the rest of the Underground...follow me."

Tori started walking down a path that Y/N had never really noticed before. On the way, her mom said, "Do you remember those times I left you, at around 12 o'clock almost every day? Well, almost every day I travel to the door that leads to the outside of the Ruins, and I talk to someone. I believe his name is Sans. We are very similar, and he is the closest thing I have had to a friend in a long time. If you meet him...give him my regards. But please, call me 'The Lady Behind the Door.' I'd...rather not use my name around anyone other than you, child."

Toriel's face was wistful. Was there something she wasn't telling?

Anyway, the monster and human soon stood in front of a large pair of wooden doors. Tori bent down and started hugging Y/N tightly, and didn't seem too keen on letting go. Eventually, though, she loosened her grasp, and stood upright again. "Please, come and visit sometime, okay?" Tori whispered. It was on the verge of desperate begging, but Y/N ignored that and answered solemnly, "Of course I will, Mom. I won't break my promise."

That gave Toriel enough satisfaction, and she started down the hallway. "Wait!" Y/N called. Tori turned halfway towards her voice. "Yes, my child?"

"I love you, Mom. I'll return soon enough."
A smile spread on Tori's face. "I love you too, my child. Be back soon."

"I will. Goodbye, Mom."

"Goodbye, my child." And with that, Toriel was gone.

Y/N turned towards the door, taking some deep breaths in and out. This is what she had wanted, right? To see the Underground. And here she was, doing what she thought she would never do in a million years a couple months earlier.

She took one last breath, then creaked open the door to a whole new world.