Kris explores ROOTS alone, having been separated from Susie and Ralsei while they search for Noelle, who, after creating the Holiday Manor dark world, spending time with her dying father and witnessing him on the verge of passing, runs off to find a cure in the form of a magical artifact that's a key lime pie, Rudy's favorite food, in the light world. The ROOTS are... Strangely familiar. Both Kris and you recognise the vivid silhouettes of lampposts, buildings, roads and of course, trees. There's no doubt - this is Hometown. While you are surprised and a bit suspicious about it being in such a perfect state, for something that should not even be here, Kris whole body starts to shake lightly and they start to move a bit slower. They clearly don't like it here. You don't understand why, at least for now.
While wandering through the town's streets, you notice a few major differences between the two versions of the place. First, everything looks much newer than what you saw earlier. The walls aren't showing any tiny cracks, the graffiti of ICE-E and the Everyman looks and smells freshly painted, the picnic tables have no rust on them and, most importantly, there's no Sans' house and the convenience store is named Grillby's. Overall, the atmosphere is much less somber and even more melancholic, as a cheery yet somewhat unnerving tune plays in the background. Finally, you approach the path past the church. You hear a few faint voices chatting about something:
"Are you sure this is a good idea...?"
"What, you scared of a big metal box? Toughen up, crybaby!"
"I-I-I-I'm not scared of nuthin', got it!?"
"Well, then catch on!"
And then it hits you: you are in a flashback, and you already know who the two voices belong to.
Your vessel becomes abnormally hard to control. They're close to having a full-on panic attack. They refuse to step more than a few times and then fully collapse onto a perfectly dusted sidewalk near the town hall. Despite their best efforts to resist you, you forcefully get them up and start marching forward, just as you might've done a year ago in a certain other save file. It seems that the corridor made of trees will never end, but eventually, you make your way to it. The shelter. Two figures stand in front of the red metal doors, one - a rowdy furry girl with antlers and unkempt hair in a flannel jacket. Second - a human child that looks to be about 10 years old. Even then, the messy bangs and a one-striped shirt give out who they are. You can't see it, but a few tears come down Kris' face. The girl looks curious but a bit nervous. The kid is clearly distressed, but tries their best to hide it.
The bird's chirping gets lost in a weird humm that comes out of the shelter's doors.
You hear a sound of a metal panel being removed and then a few electronic clicks.
"Come on Krismas, at least appreciate the effort that I had to go through in order to get these three! Sneaking into our basement to search through the boxes, distracting your dad long enough to dig through the flower's soil, and flipping over every single document in that pastor's office are all equally hard work!"
"Dessy, maybe we shouldn't do it... I'm scared..."
The girl stops clicking.
"If you don't want to do this, then go home. I've done too much to turn back now. Besides, this is the only thing left in this goddamn town that we haven't seen yet."
"B-b-but..."
Dess' voice gets a bit softer.
"Kris, I know I don't have to rope you into this, but you asked to go with me in the first place. Be brave, pal! Don't you want to see what's here as much as I do? No matter what awaits us there, I promise you that I'll always be with you..."
The kid's sobbing fully stops.
"R-r-right, Dessy. I trust you."
"Now that's the spirit! Finally I've almost finished! Well, now we'll see if this whole thing will actually work."
You hear one more beep and then the slow sound of the doors opening.
"I'll come in first, and you hold my hand, okay, Kris?"
"Okay, Dessy."
After hearing the footsteps getting fainter, you decide to follow the duo, seeing that you have no other choice.
You continue piloting your barely responsive vessel by force as you both step into the darkness.
Less of a hypothetical scenario and more like absolute cinema fanfiction
Thanks 
I mean, I tried my best but the dialogue might be a bit too dry and not in style of the characters.
I'll write the second part today. I wanted to post this as a single big post but I realised that there's just too much to write for it to be one single wall of text.
Also I should probably change the category to fangames since this is more like a fangame of sorts.
It's pretty damn good
reads kind of like an SCP tale
I mean this is a Very Disturbing Start to the Fight, Also Fun that Sans’ shop is grillby’s that’s a Good explanation for where the hell grillby is.
Also
Tension Is Bound By ROOTS, TP Gain Increased by PANIC
(Sorry if that part is weird I just wanted to add a Battle Start Note)