Disclaimer: Naruto (Masashi kishimoto) and Undertale (Toby fox) both belong to their respective owners. Thank you for reading;) Also, I got some inspiration from the fanfic simply titled "Undertale" by pichayou.

'Naruto'= thoughts

Naruto= normal

OoO= short cut/break XxxxXxx= long cut/break

Naruto= narrative

Part 1

Chapter 1: Rift

Long ago, two races ruled over Earth: Humans and Monsters

One day, war broke out between the two races

After a long battle, the humans were victorious

They sealed the monsters underground with a powerful jutsu

Many years later...

His bright red ball teetered through the mouth of a small cave opening. Naruto stood there, dumbfounded at what happened. He hesitated. "Maybe I can just get another ball-but, sensei'll be upset when he finds out I came here..." A scared sigh escaped his breath and he ventured through. 'I'll be back in no time!'

Though, he guessed the 'I'll be back in no time' part didn't include twisting his foot on a loose vine and falling into a pit.

OoO

The dim glow of the surface light eventually woke Naruto up, he felt the ground beneath him was nothing but a bed of golden flowers. After a couple of seconds wasted to fidgeting, he rolled off the flower bed. "...I guess I won't be back in no time..." Naruto muttered.

He took the only passage way out of the room and found himself gawking at an odd looking, gray door. "Hey! Is anyone here?" He walked through.

"HELLO?!"

"-hey, kid, that's enough shouting."

"Huh?" Naruto scanned the black room, no visible signs of anyone. "A-Are you some kind of ghost?!"

"What the-no! Are you brain dead, kid? Look down!"

He did as the voice told and saw a beaming yellow flower staring right at him. "...! GWAHH! F-flowers can't talk!"

"Well I'm a very special flower. The name's Flowey and I can tell just by looking at that clueless face of yours, you're new here to the Underground, aren' tcha?"

Naruto slowly nodded.

"Well, it's your lous-, lucky day that little 'ol Flowey's here. How about I teach you the ropes?"

"No."

"See that s-wait...NO?! What the heck are you saying, kid?!"

Naruto gave Flowey a cheeky grin. "There's no way I'd wanna learn anything from a freak like you!"

"Y-you damn brat! You're going to die out there without my help and someone else is going to take your soul! AND I CAN'T ALLOW THAT."

"...my soul?" It was the only thing Naruto could pick out of the psychotic Flower's words, and the only thing he could say before being surrounded by an army of seeds. Naruto felt something powerful manifest on the side of his chest, his hand grazed over a small, but beaming red heart full of passion. 'Is...is this it? My soul?'

The seeds danced around Naruto on all sides, there was no way he could escape without getting pelted to death with the thousand of bullets.

"That's your soul right there!" Flowey said between chuckles. "It's weak, yes, but it can grow strong by gaining LV, or Love, and gaining EXP. How do you gain love? By getting touched with these friendly pellets! Hehe. They won't hurt you!"

Something deep inside told Naruto the Flower was wrong.

"Stop cowering down! You want to earn love, don't you?! You want to grow stronger, right?! Then the ENTIRE underground will recognize you and...and..." His face started twisting into a more threatening expression. "And you won't be treated like the rightful scum you are!"

"...I..."

"HEHEHEHA! For the sake of everyone, JUST DIE!"

Nothing happened. He raised his head, the once menacing flower and his army were now replaced with the soothing darkness.

*patter

*patter

Naruto's ears perked to the sound of soft footsteps approaching him. 'That's it! I'm not letting this one push me around!' He shot straight up and lunged for the incoming beast. "GET READY!"

"-oomph!"

'It feels really soft...I-I don't think this another flower!'

"Are you...hugging me?" A voice asked, it was so soothing and gentle, his eyes wandered up. She was...well...what on earth was she? Naruto managed to tear himself away from the warmth to get a good, long, old-fashioned stare at her. "No, I...A-are...a...you..." He stammered, unable to complete his sentence.

'Oh my, he's so scared, he's unable to complete his sentences!' Naruto didn't think it was possible, but she spoke in an even more gentle and soothing tone. "You don't have to be afraid any more, child. I am Toriel, caretaker of the ruins, and I'm here to guide you."

"-Everyday I pass through this place to see if any newcomers have arrived, you're the first human to ever fall down here in a very long time. Come, I'll guide you through these catacombs."

Naruto followed Toriel to the next room, it was a room filled with roses and...determination. On both sides, a staircase spiraled towards the door.

Toriel stopped when they reached the next room. "The ruins are full of puzzles, child, you'll be encountering all sorts of them, solving these puzzles are key to moving from one room to the next and I want to teach you everything about them since you'll be living here." She moved over to a group of buttons by the door and stepped on the four outer ones, opening the door. "See?"

"Right! Got it!"

Naruto ran inside the following room, he padded over the bridges bulging with pale, blue water and flipped the last switch in the hallway. But nothing happened.

"..."

He flipped it harder, but nothing happened.

"Oh, dear..." Toriel hurried over to Naruto and pulled him away from the switch. "Silly child, the ones you need to activate are clearly labeled." She clearly emphasized on the clearly.

Naruto's head sunk.

"But no need to worry, I activated them for you."

Naruto's head raised.

"Come follow me to the next room."

The room after was small and compact, it contained no puzzles, but a single, lonely dummy. "As a human, monsters may try to attack you and you'll engage in a fight. However, worry not, you don't have to fight said monster, you can simply strike up a friendly conversation."

"Huh?"

"I know it seems confusing, so why don't you try out your conversational skills on that old dummy over there."

"You want me to talk to a dummy? That's really stupid, y'know! How am I gonna get stronger from talking to it?"

"Stronger? That flower has filled you with nonsense. If you simply talk to it, you have the chance to become its friend. And in my opinion, that's a far more fulfilling reward than becoming-" She stopped, the child was gone.

"Huh? Little boy where did you-"

The boy was talking to the dummy.

"Hey! The name's Naruto! What's yours?"

"..."

"You're not up for conversation, huh?"

"..."

'So eager to find friends, he must of been a lonely boy.' "Uh, that's enough, child." Toriel said. "I'm very proud of you, but I thought you didn't want to talk to the dummy." She teased.

His face was scarlet. "T-That's not true! I was just doing what you told me, Goat lady! Come on! Lemme talk to a real monster!"

"Alright, follow me."

The room followed was another long hallway with a twisted path that stretched all the way to the next door. He didn't stray from the path until he reached the very end where a frog was staring down at him.

'A real monster! What do I do...just talk to it, right?' "The name's Naruto! Uh...I really like frogs?"

'I'm not sure what he said, but for some reason, I feel flattered!' Froggit gave Naruto an I'm-really-trying-to-like-you-but-I'm-still-going-to-attack-you-anyways smile, he hopped towards the spiky blonde but stopped dead in his tracks. The deathly rays of Toriel pounding down on him was far too much for him to handle. At that point, his choice was either to face Toriel or hide in the corner.

Toriel's glare intensified.

So corner it was.

Naruto walked back to the safe comfort of Toriel, her warm, fuzzy paw wrapped around his hand. "This is the puzzle," Toriel explained, as they walked past the corridor. "I'm sorry for not mentioning it earlier." The puzzle consisted of an array of sharp spikes laid out across the floor.

She saw his face grow pale. "But I think it's best if I help you through this one-it's um, rather dangerous."

Toriel guided Naruto through the 'puzzle' and into the next room, she stopped and he silently prepared for her next action. "I'm sorry, but I have something to ask you..." She felt something swell in her throat. "Can you please walk this room...by yourself...please forgive me." She shuffled off and swiftly hid behind a decaying pillar.

"Oh-I feel so bad." Toriel quietly murmured. 'Perhaps he feels like I didn't want to be around him anymore, maybe I should...' She felt a tug at her paw. The little child was standing before her, wearing a big, goofy smile on his face.

"Hiya, Goat lady!"

"You completed it so fast...!"

"Yeah? That challenge was way too easy for me anyways!"

"Well it looks like you've grown to be a very independent boy...uh...I'm sorry this is so sudden, but I have business I need to attend to and I must go alone. So please do not follow me, it's too dangerous to explore by yourself," Toriel pulled out a small, junky box and tucked it between Naruto's hands. "Here; it's a cell phone. If you need anything, just call." Then, just like that, Toriel left.

Naruto gave the cell phone a tight squeeze before cramming it inside his pocket, he adjusted his green goggles then grinned. "Heh, there's no way I'm staying in this smelly place!" And just like that, Naruto left.

A/N: Thank you for reading this, I know it's strange I hadn't touched upon Naruto's feelings, but how he feels about landing in the Underground, how he truly feels, will be touched upon later.