Kris

"take a seat, kiddos." Without waiting for us to react, Sans flicked his hand towards us, and we were thrown back into big comfy chairs behind us. His pinprick pupils began to fade.

"now... we need to have a little chat," he said darkly. Susie and I looked anxiously at each other. "recently, i've been feeling a huge imbalance in the timelines, and it seems to lead to you two."

"What?" Susie asked, clearly very confused.

"look kiddos, i don't know you, only that something's been happening that was a result of you two. have either of you, say, visited a different timeline or universe?" I felt a crawling sensation on my back and began sweating.

"I have absolutely no idea what you're-" Susie paused. "Wait! Kris, didn't you say something about-"

"No." I cut her off. I still didn't trust this guy.

"kid, if you know something, you gotta tell me. if something bad is happening, i need to know so i can fix it. i'm the only one who can."

I still didn't feel comfortable telling him anything, so I looked away. He sighed.

"i didn't wanna have to mention this, but i think a timeline is dying, collapsing. if that happens, everyone in it and every memory of it will be erased. all the innocent people living there will die. nobody will survive."

That shook me. I knew that keeping information to myself would only condemn them.

"Alright... I'm... I'm not from here. I'm from a different timeline. Yesterday, I woke up in this world, and I- I have no idea how I got here."

Sans pondered that. "did something happen to lead up to this? a huge change that could've caused the timeline to panic and send you here?"

"I..." I thought back as recent as I could in the other timeline, but I couldn't reach all of it. "I don't remember... Wait, no! I don't remember!? How could I forget this?! I know something important happened, but I can't reach that-"

"kid! kid! calm down. i really hate to say this, but from what you're describing, it sounds like your world is dying. your memory of that place is slipping away, day by day. there is only one way to fix this, and it's extremely dangerous." Alarm clouded my thoughts.

The idea of never being able to return home... I had thought that this was some sort of temporary thing, and any day now, I'd wake up in my own world, go to my own world, and be with my own girlfriend. I missed her so much. I missed having her arms around me. I missed seeing her gorgeous buttercup eyes filled with love for me. I missed the soft tenderness of her lips against my own. The idea of never having that again...

It was unbearable.

"I don't care how dangerous it is. I'd do anything to save my home."

"you don't understand, you'll die if you fail. all memory of you will be erased. you'll be trapped in limbo for the rest of time."

"Good. I'd rather die than never be able to go home. I need to get back." Sans nodded. He understood.

"alright. meet me at my shop after school at 3."

"Wait, wait, wait, hold up! I want to help!" Susie piped up.

"You can't- it's too dangerous," I reasoned.

She looked me in the eye. Although they sparkled with a familiar look of determination, her eyes didn't share the same breathtaking luster I had grown to love and need so deeply. My soul ached.

"Look Kris, even if I'm not the brave Susie you know and love, I'm not helpless. I'm perfectly capable of helping, and therefore I want to. So let me." With one last look at her, I realized she wasn't going to give in.

"Alright. Thank you, I appreciate it."

"then you both know the plan. i'll see you there."

With one last flick of his hand, Sans was gone.

~~~~~~~~~~

Quick little explanation

Every day that Kris spends in the universe of Remember, that's one more day they can't remember from Don't Forget. They don't remember Susie dying, all they know is that she's gone and in danger.