Underfalls: The COMPLETE Trilogy To A Gravity Falls/ Undertale Crossover

❤️Chapter 3: A New Threat❤️

MabelPOV

I dashed out of the Mystery Shack, giving a quick wave to Papyrus and Soos on the way out. Everyone thought I looked happy, but to be honest, I wasn't. I was confused and scared, and wasn't sure what had happened on the surface after I moved Underground, and what happened to everybody. Grunkle Stan and Great Uncle Ford are gone to explore the world, Soos is the new Mr. Mystery, and Dipper's still here... I'm sure Sans is upset too, since both of our brothers are in the same place, but it gets me worried that he might start conflict again.

"What's wrong, kiddo? Something's wrong, I know." Sans wrapped an arm around me as he pulled me closer to him, comforting me the best he could. "Well... Now that both Dipper and Papyrus are back... Im scared he'll do something again and it'll be the same again-"

"I know..." Sans cut me off, kissing my forehead. "I'm sorry if I get out of hand... It's hard to see my brother lost so many times, and there's hardly anything i can do about it... I just wish... I could protect him from anything, and we'd stay happy forever..." Sans trailed off as he slowed our pace and I grabbed his hand as I whispered, "It's okay Sans... Papyrus is safe with us.... Don't worry..."

"I have every reason to worry! Papyrus is my brother, no matter what. I always have to worry about him... Just like you do with your brother..." Memories staryed flooding my head as I Dipper came to mind. Was it really just Chara killing every monster? Or really, deep down, Dipper was a true dirty killer? I never would've guessed that Dipper would be this way, but... I guess things could have happened while Dipper was out on missions and I stayed back... But could Dipper really change into that?

I was pulled out of my thoughts as Sans suddenly embraced me, tears falling from his face. "Thank you..."

"For what?"

"Jut being there. I thought you would haye me after I took revenge on your brother, and you would never care again. You could've ended our adventure there. You could've just left me with no one. But you didn't. You wanted to help me so bad to get Papyrus back. So at least I owe you a thank you..."

"Y-you don't need to thank me... I just felt bad that you were going to be alone if I didn't help you."

Sans returned to his origonal posistion, wrapping his arm casually around my shoulder. He brushed away the tears, and looked away, acting like none of that just happened. "Sorry..." Sans muttered as he gazed off into the distance.

•••

After walking for some distance, it became almost dark. "You hungry, kid? We could go ahead down for the night and have some Grillbys-"

"Actually," I said, grabbing his hand as I tugged it in the direction that was back to town. "If you don't mind, I could take us out to eat tonight. If you don't mind that is..." Sans gave a calm nod, and casually strolled beside me back to town.

I took him to Lazy Susan's diner, not far from the Mystery Shack. I figured after dinner, we could pick up Papyrus and we could go home for the night. I opened the door, letting him go in before me, and as soon as I entered, I was greeted by the familiar smells, sounds, and sights of the friendly little diner. Since all of the barstools were taken at the counter, I led the way to a little booth that I've sat in a few other times I've been here. He sat across from me, tapping his bony fingers on the table as we waited for Lazy Susan to come and greet us. "Worried about Papyrus?"

Sans looked up, and faked a little smile, moving his hand from the table, to his chin, swallowing before speaking. "No offense or anything, but I don't trust your brother. He may have said that he's changed, but that doesn't change what he's done in the mess." I took a breath as I was about to argue, when Sans continued. "You didn't deserve to clean up your brother's mess. In fact, if you didn't fix everything for him, I still would've taken vengeance for my bro. He doesn't deserve you fixing everything and he just ignores it like he didn't do it in the first place! It's his fault for starting this mess in the first place and-"

Sans suddenly stopped as two figures walked over to our booth, listening to Sans rant. I recognized who it was as soon as the taller one spoke, slamming her palms on the table. "Sup punks?! There room for two more?!" I grinned and waved to Undyne as I slid over to Sans' side of the booth, Undyne and Alphys sliding in across from me. I had finally gotten a chance to meet them on my first day of school, when Toriel wanted me to know every monster that once lived Underground. They seemed really friendly, and it seemed they tried ignoring the fact that they were both once killed by my brother.

Alphys gave me a small smile, and a shaky wave as she settled in the seat beside Undyne, and the fish put an arm around her lovingly. Lazy Susan soon approached us soon after, and her eyes lit up at the sight of a familiar face. "Ah, well hello there, Sweetie! Who are your friends?"

"Hi Lazy Susan! This is Sans the Skeleton, Alphys the Royal Scientist, and Undyne, Head of the Royal Guard!"

"And I'm guessing this Sans fellow you're sitting by is your boyfriend?" Lazy Susan asked me as she grabbed her notepad. I felt my face heat up, as I looked over at Sans, his face a blown-out blue blush. "We're... We're not dating..." Lazy Susan nodded, as she grabbed her pencil, waiting for us to order.

•••

"Ok enough chatting, lets go Mabel," Sans said fiercely, grabbing my wrist as he worriedly dragged me towards the Mystery Shack. I waved a quick farewell to Undyne and Alphys before heading for the shack with Sans. "Im sure he's fine Sans-"

"And how would you know? For all we know, my brother could be DEAD."

"Sans, stop talking like that, Papyrus is fine, you watch, he'll be here, just like we left him-"

"He's gone..." As I followed Sans in, I realized that he was right. The Mystery Shack was empty, and only a single not from Soos remained, saying that he was out to eat with Melody tonight, and the Shack was closed until morning. Just one question rattled in my head:

Where was Papyrus?