Grillby's House: A Narrative Fiction
Luckily for Sans, Papyrus was out of the house longer than usual due to both his Royal Guard training with Undyne and searching around for him, unaware that he was already at home. They're usually together, but Papyrus has noticed that every once in a while he just suddenly disappears. On his way back home he checked for his brother at a few of his nearby sentry posts, stopping by Grillby's as well even though he wasn't very fond of the place. After learning from one of Grillby's patrons that Sans hasn't been visiting as much as he usually does, he knew something was up.
Once he stepped through the door of their house, he was greeted by absolute darkness. "Sans, I'm home!" he announced in his usual boisterous voice to the pitch-black room