Sans appeared in a small cavern in Waterfall before weakly collapsing against the wall and closing his eyes while Chara's SOUL appeared above him glowing brightly with Determination.

"There can't be many monsters left… who have I missed so far? It's getting so bad I can barely even think." Sans whispered to himself before his eyes widened. "Oh yeah, now I remember."

With that said he weakly got back to his feet before frowning and walking back out into the quiet and nearly empty Waterfall to look for the last remaining Monsters he needed to kill in order to help Frisk stop the resets.

Almost on cue a faint humming caught his attention as he turned to see one of the only monsters left in the Underground as he approached only for the monster, Shyren, to turn and gasp in horror.

"Sans… what are you…" Shyren started fearfully while backing away from him only for her eyes to widen when she saw him collapse to his hands and knees and start breathing heavily as though in severe pain. "What the, what's happening to you…"

Shyren never finished her sentence as a single bone impaled her turning her into yet another pile of dust as Sans shuddered before trying to get to his feet only to close his eyes sadly before vanishing again.

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"What are you going to do when we get to the surface Onionsan?" Frisk inquired with a smile.

Onionsan smiled back. "I'm going to live in the ocean."

"That sounds awesome." Frisk mentioned before frowning. "Oh, I guess that's the end of the room, take care of yourself Onionsan."

"Yeah, thanks for passing by. Stop by again if you get the chance… in Waterfall." Onionsan replied before sinking back under the surface of the water as Frisk closed her eyes before continuing through into the next room only to hear faint humming.

"Hello?" Frisk asked. "Is someone here?"

A female monster suddenly froze and tried to hide in the corner of the room.

Frisk frowned at that before slowly walking over to the monster and humming a gentle tune causing her to look at Frisk before slowly singing to the melody.

"My name's Frisk, it's nice to meet you." Frisk smiled as she stopped humming.

The monster looked at Frisk fearfully while trying to move away from her only for Frisk to frown and start humming again while gently offering her hand.

The monster started singing along to the humming again before pausing. "Who… are you?"

"You have a nice singing voice." Frisk mentioned. "What's your name?"

The monster looked down shyly. "… Shyren."

Frisk smiled reassuringly. "You have a really nice voice Shyren."

Shyren turned to Frisk hearing that. "Really?"

"Yeah, can you sing a little more?" Frisk requested.

Shyren's eyes lit up slightly before nodding. "Well… ok."

Frisk smiled before humming again as Shyren sang along to the melody for a few minutes.

Suddenly Frisk frowned. "Oh, I need to go now. It was nice singing with you though."

"I agree… it was nice." Shyren nodded as Frisk walked into a side room only to notice a piano.

Frisk closed her eyes before sitting at the piano and slowly beginning to play the melody she'd heard in her previous trips through the Underground.

The moment she played the final note a hidden passage opened in a nearby wall.

Frisk looked through the passage to see a red orb before gently shaking her head and walking off without the orb while continuing on her path. 'Sans… I promise when the time comes, we'll all be there, and we'll be able to stay on the surface.'

With that thought in mind Frisk continued along the path only to smile at a stone statue with a music box inside of it. Seeing the statue, she made a point to walk ahead to a trash can full of umbrellas and put one over the statue to let the music play before picking up a second one and walking through the area of the Underground where it started to rain.

"Huh, oh you have an umbrella, that's great." Monster Kid mentioned as Frisk walked past.

Frisk smiled seeing him. "Do you want to come with me?"

"Alright, thanks." Monster Kid smiled before running under Frisk's umbrella.

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"I don't know if I can make it all the way Frisk, my SOUL feels like it's going to break apart at any moment." Sans whispered weakly as he looked at the ceiling of the cavern and put a hand over his chest as Chara's SOUL appeared. "That reset definitely didn't help and yet… I have a feeling it's only going to get worse from here."

He closed his eyes saying that as the image of Frisk's heartbroken face appeared in his mind and he shook his head.

"Heh, you went through this nightmare to help us… I have to at least try and go through with it."

With that thought in mind Sans struggled to his feet before slowly moving forward to the end of Waterfall only to pause when he saw two more Moldbyggs moving to try and stop him.

One of them tried to attack Sans only for him to dodge to the side and raise his arm to form a wall of bones only to suddenly wince in pain as they turned to dust causing the Moldbyggs to pause seeing that before a red glow enveloped Sans body and he weakly got to his feet before a Gaster Blaster appeared next to him and vaporized both of the Moldbyggs.

With the death of the two monsters Sans suddenly gasped and clutched his chest before his SOUL appeared in front of him revealing it was covered in hairline cracks and Chara's SOUL was glowing with Determination.

"Frisk… this is going to kill me." Sans frowned before taking slow deep breaths. "I don't know how strong you humans are… but if you could get through this without dying that's just insane… I guess, the stronger your SOUL the more bad things you can endure, but at the same time it would explain how you were in so much pain after going through with it."

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"Hey… Monster Kid?" Frisk asked before pausing. "What do you think of Undyne?"

Monster Kid turned to Frisk in confusion. "Undyne's the best, she's super strong and always beats up the bad guys. I bet one day she'll be the one to get us to the surface along with the king."

Frisk nodded at that. "She really cares about you all doesn't she?"

"Yeah." Monster Kid smiled. "With her hunting the humans I know we'll be free in no time."

Frisk frowned briefly before smiling again. "From what I can tell she's definitely a special monster. She's in charge of the Royal Guard right, and reports directly to the King?"

"Oh… yeah I guess that's true. Actually, he stopped by my school one day when we were learning about flowers… he told us to call him Mr. Dreemurr, and he taught us a lot of cool things about responsibility and other stuff." Monster Kid explained.

"That must have been exciting, the king of every Monster teaching you something himself." Frisk admitted. "You must have been really happy."

"It was cool, but now I'm wondering what it would be like if Undyne came to school. I bet she'd beat up all the teachers." Monster Kid said excitedly only to pause. "Actually… she probably wouldn't do that, she's too cool to beat up an innocent person."

"Hopefully we can see her again soon." Frisk mentioned. "She's your role model, isn't she?"

Monster Kid smiled. "Yeah, you can say that. I think almost every monster feels the same way though."

Frisk nodded with a smile before closing her eyes. I just hope once we're on the surface… she'll be as willing to forgive me as you were Sans.

As the two of them continued walking Frisk glanced over and noticed a large castle in the distance before they reached a fairly high ledge.

"This is way too high isn't it?" Monster Kid asked.

"Yeah… I guess we won't get to see Undyne." Frisk frowned.

Monster Kid frowned before pausing and looking down in thought. "You really want to see Undyne, don't you?"

"Yeah, I do." Frisk replied. Just maybe not for the reason you do.

Monster Kid nodded before facing the ledge. "Here, if you climb on my shoulders you should be able to make it up there."

Frisk turned to Monster Kid and smiled. "Are you sure? Well… thanks."

"It's no big deal, I always find a way to get through." Monster Kid smiled as Frisk carefully climbed up the ledge. "I'll see you around."

With that Monster Kid turned and ran off as Frisk closed her eyes and smiled. Not much longer now Sans, I'm more than halfway there, but… I just hope I can reach the barrier in time.

With that thought in mind Frisk continued along the path only briefly glancing at the words on the wall detailing how humanity attacked the Monsters out of fear and how so many of them were killed without a single human SOUL being taken only to reach a bridge and pause just as a blue glow appeared in front of her moments before a spear shot up from the ground.

Frisk immediately started running as more blue glows and spears rose from the ground at an increasing pace and Undyne's footsteps were echoing nearby as she closed in on Frisk.

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"This can't be real can it Undyne?" Papyrus asked fearfully. "Sans wouldn't do this; he couldn't do this."

"I want to believe that Papyrus, but the evidence is all around us." Undyne frowned kneeling down next to another pile of dust. "He said he'd tell me what's going on when we reach the end of Waterfall, that mountain but…"

She paused before turning to Papyrus.

"Undyne?" Papyrus inquired hesitantly. "What's wrong with you?"

"You wanted to join the Royal Guard right? I need you to find the River Person and get to Asgore. He needs to know what's happening."

Papyrus froze in shock hearing that. "Undyne… I…"

"It's important Papyrus, he could be in danger." Undyne told him. "I'll try and get Sans to stop but if I can't you need to be able to protect the king. If there's anyone in the Underground who can stop Sans if I fail… it's you."

Papyrus closed his eyes and looked as though he was about to break down hearing that before weakly choking out. "I… understand… Undyne."

With that said he turn and ran back to where the River Person usually waited in Waterfall as Undyne turned the opposite direction. "Papyrus… One way or another, we have to stop Sans. I'm sorry."

With that she ran to her inevitable confrontation with the lazy skeleton.

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Frisk continued running away from Undyne while dodging the spears she rose from the ground only to lose her balance and trip as her eyes widened in horror as one of the spears hit her in the arm causing her to cry out in pain.

No, I can't fail… I promised Sans I would be there at the barrier so we could stay on the surface this time. Frisk thought as she weakly got up and held her arm while continuing to run before reaching the end of the bridge and fearfully turning around to see Undyne staring at her.

"Wait, please you don't understand. I can't let you…" she started as Undyne formed a line of spears that all struck the bridge simultaneously causing a large section including the part Frisk was standing on to fall as Undyne watched.

(Sans has managed to kill nearly every monster in Waterfall but the pain from the increasing Determination in Chara's SOUL is drastically slowing him down and meanwhile Frisk has fallen off a bridge in Waterfall. Next chapter Frisk will continue traveling through Waterfall. As always any reviews or critique is appreciated.)