(Sans POV)

My eyelids were getting heavy, I tried to keep them open, but sleep had already overtaken me. Lulling me into a sense of security.
The peace didn't last.
"Sans!"
I shot up finding myself in an entirely new place.
"Frisk!...Woah, you've been busy" I took this chance to look around at my surroundings, a light glowing pink coated the walls and floor. "What even is this place?...Oh god. Frisk?" They looked like they were stuck in some sort of beam, in a comatose-like state. I remembered W. D. Gaster being in a similar deep sleep.
I ran over to where Frisk was, overwhelmed with joy, I didn't even want to think. I reached out to grab them, whispering comforting things into their ear. They were coming to, and my heart felt like it was going to explode from my chest. They were so soft, so quiet compared to the monster that held them hostage.
I found myself gently taking their arms as they shifted out of sleep. But the second they looked at me, all I could see was t e r r o r pure terror.
Being the stupid person that I was, I thought I could fix this...but how can you help someone who suffers from PTSD? Frisk looked up at me like the monster that I was. They were past breaking point, and there was no fixing what had already been broken.
I tried to communicate with them that I wasn't the bad guy, nor was I going to hurt them, but when I hugged them, it must have triggered something because they pushed me, then crawled away from me, shaking violently. They landed on the ground, a few feet away from me, their tears starting to pool on the floor. They didn't speak a word, I don't think they could've managed it anyways.
I figured out pretty quick that their condition was nothing short of horrific. I wanted, no, needed to help, but it was more on how. How do you approach someone who's deathly afraid of being approached? The answer; you can't. But...heh, we already made it clear that I 'd go through hell and back for this kid.
I tried to comfort the kid again, but they just screamed and told me to stay back. I knew this would happen, I don't know why I was so surprised though. I sighed and turned to a familiar persona, Comic Sans. Heh, still gets me. 
"Alright kid, lay it out for me, tell me whatcha' need. I want to help you out."
"Mmmm"
But, I guess this would be a long, painful process. No kidding, I could feel the fear radiating from the kid.
"Hey, kid, look at me. I want to see the real you, not just this...shell of yours. You aren't a turtle. I know the buggers when I see them, and they don't look like a hypothetical short haired little punk who thinks comedians are scary. Hehe, sound familiar?" The kid was giggling, but, they didn't stay for long. "But seriously kid, please, let me help you..."
"Nnnng" 
As I sat on the floor, I realized that humor, while being a damned good medicine, would not heal them so easily. My resolve was starting to shatter. 
I laughed awkwardly, rubbing my hands together.
"Hehe, you can't blame me for trying...huh, kid?"
I tried to keep the smile on my face but...even Frisk knew I couldn't keep smiling. I messed up, and I'm not just talking about in this dream I was having right now. 
"Sorry kiddo...I guess I tho-"
"I tried once..."
"...What do you mean?..."
The walls started shaking, rumbling almost. Frisk told me to run, to get away because their soul couldn't support the both of us. I had shaken my head and told them that no matter what would happen, from now on, I would protect them. But before I could do anything else, a gaping hole formed beneath me and I fell, yelling their name, and Frisk yelling mine.

Y'know, falling would have come as a surprise, if I didn't have a way to cheat out of it. Using my magic, I kept myself from falling. It was dark, obviously, nothing I had ever seen before. So, I was careful as I tried to slow my decent. It was calm...silent. Frisk's soul...it was in no immediate danger but still...
"Frisk...damnit kid, why didn't I put two and two together? Obviously you were injured...." I started yelling, hoping that Frisk would call back to me.
A voice called out from the darkness,
"Sans" I couldn't tell who's it was, but it sure wasn't Frisk's.
"Who's there? I swear to god if you even touch them I'll-"
"Sans. Don't be foolish, look around" And so I did, another light source, the same glowing pink that I had found on Frisk's soul.
"What the hell....Who are you?"
"A friend. I'm just trying to help, don't you know how to greet an old friend? Turn around and shake my hand." It was Gaster. W.D. Gaster to be exact. He used to be the Royal scientist until he fell into his own creation. But why is he here? Why now?
"Heh, has been a while hasn't it...I would ask how you are but...you know how it is."
"Ah, do not worry my friend, it is not formalities I seek...but in any case...I am glad to see you in good company...6 souls I sense?"
"Uh, yeah...it's a uh," I cleared my throat, "...long story"
"Don't indulge yourself in the story for my sake, friend...though it is peculiar though..."
"(Damnit just stop) Why are you here Gaster?"
"Well, I only wanted to guide you. Their soul is in great agony...an agony granted you aided in. So...I wish to show you the value of human determination."
"Wait...you dragged me down here for this?! Seriously?"
"Patience, this is how to help your human child"
"They're not my--"I sighed, "Just show me."
Gaster pulled up Frisk's soul before he continued.
"First of all..." He then made 6 streams of color, light blue, purple, pink, orange, light purple, and lime green flow into their soul. "Do not underestimate me."
I was shocked, what was he doing? "What are you doing?" 
He took the multicolored soul, and held it up,
"Relax, papa bones..." He brought the soul closer to me, "I am letting the souls undo the damage of your presence."
I stared into the soul, feeling empathy with the kid. "Of course, me being there must have made Frisk unstable." 
Gaster turned to me, "Do you know why their soul is unstable?"
"I killed them, that's why."
"Quite wrong. After some time, they forced their soul to split from the corrupted half...to escape you."
"Then the soul that was in Frisk's body, before I killed them, I mean....it was that deamon's. That explains why there wasn't a RESET."
"Quite! So currently, this is where we're at: Frisk is free to return to their body. There is, however, a problem." 
My eyes widened.
"What is it?"
"After two reloads, I am sure Frisk realized that they could not get you to understand. They lost hope...they lost, determination. So they hid away in the closest object."
"Damnit..."
"So, their injuries as a soul are not lethal, however, add to that a loss of determination...and there lies our problem. Without determination, an injured soul is fragile. So, if Frisk should feel unworthy when returned to their body,"
Gaster showed me a glowing image of Frisk with their soul in front of it, "then the soul will oblige." The soul split in two, I gasped, covering my mouth.
A horrible feeling of regret washed over me. I couldn't stand any longer, I leaned against Gaster.
"My friend, are you feeling well...? I feel the souls instability."
"Uhffff...I feel, odd. I did this, I hurt them, this...innocent kid. I hurt them Gaster, I don't even know if I can help them...and with the way things are going, I don't think I should."
"...I know. I know, Sans...the emotions of the souls are conflicting with yours."
"Conflicting? You mean their effecting me?"
"It has no relevance. As long as you feel the same way, Frisk still has a chance." Gaster helped me stand up straight again, his arm still on my shoulder. "Use the souls magic to keep Frisk alive. In that time, their injuries will heal...but determination, not so easily."
"What can I do about that?"
"Give them a reason to live. To want to try again. And in that, you'll find a solution." 
"Makes sense, thanks Gaster." I looked down to my stomach, finally able to float on my own. "They'll take good care of you kiddo."

I woke up gasping. Oh, right, I was in a dream. I held my stomach patting it lightly. I'll get this figured out. I sat up, regretting it immediately. Ugh, leave it to me to sleep so awkwardly. I popped my neck, getting all of the kinks out of it. Heh, I must've slept like the dead, and if we're still going on about puns, then I guess you could say that the kid was getting a little...Frisky. Yeah, they had tickled my ribs...I may be a funny bone, but being tickled is not a humerus matter. I was dying by laughter, no pun intended. I lifted up my shirt to see Frisk's soul bouncing off the walls of my stomach. The other souls were being dragged around in Frisk's strange run. I tried to compare the kid's behavior to what I had seen.
"Frisk...(You're afraid) what could be making you so panicked?" Then a brief though occurred to me. The  flat area which I had seen Frisk in, had been in the soul, which could only mean that Frisk had no idea their soul was actually with me.  All they knew was that I had fallen...no wonder they were in such a panic. So the only communication we had was through, magic.
I looked down at my stomach, sighing softly before getting my magic flowing again. 
"Hey, don't know if you can hear me, but, erm, I'm good, ya know? I'm okay just...had a bad time. Heh, get it? No biggie. Besides, we've got a way to bring you back. Personally, I wouldn't want to miss that cuz kid...y o u ' v e g o t s o m e e x p l a i n i n g t o d o."