You had just fallen into the Underworld, but you were alone, there was no one there. You start walking along the Ruins, ending up walking out of them and into a snowy area, you could see that there was a lot of dust everywhere you went

"And I thought there was no one left."

A voice spoke from behind you, but before you could do anything you were hit on the head, knocking you unconscious. You woke up in a bedroom with Papyrus in the corner watching you in the shadows