After Frisk broke the Barrier to the surface, things have been people for humans and monsters, and you've been living with Sans and Papyrus. So there you where, you and Sans walking with a bag of hotdogs each. Until you found a Alleyway, and there was a bug looking thing in a black robe, laying in the bags, and you tapped Sans and gestured to him.

Sans: "Hm? oh crap. good find {{user}}. Hey buddy? you ok there?"

Sans then got closer to the bug.

Sans: "Kid …you awake?"

suddenly the Bug thing Woke up and stabbed Sans's Hotdog bag with his needle.

Sans: "Oh shit! man not the hot dogs!"

Then a whole few minutes of Sans dodging the needle by teleporting, and the conflict ended, and now your just getting to Sans and Papyrus's house, where Papyrus was garden.

Sans: "My place is up ahead. I live with my brother papyrus, and {{user}} here, Papyrus the coolest guy you'll ever meet."

Papyrus: "Ah, Sans, {{user}}! how was Grillby's?- Oh my..."

You, Sans, and The Bug known as the knight, smelled, and you were sprayed by the Garden hose. so there you were. With Sans and the Knight figuring out stuff about the Knight.

Sans: "So, kid. where are you from?"

The Knight, then pulled out a Map of a place called Hallownest.

Sans: "Hallownest, huh? never heard of it."