They could time travel. Coming to this sort of conclusion had been ( understandably ) had taken a bit of time, testing, and disbelief; but after opened their eyes after distinctly hearing their soul shatter into tiny pieces and completely resetting their journey through the underground— Frisk was inclined to believe it. They found themselves with the ability to SAVE and LOAD laid across their young hands, and they could do it just by wanting to. With just a thought.
So, being an energetic nine year old child, Frisk decided they rather felt like playing around with their new found ability that, apparently, gave them free reign to do as they pleased without consequence. After all, they could simply RESET afterwards. . . and no one would be any wiser. They went back to see Toriel again; to listen to her stories by the magic fueled fire, eat butterscotch cinnamon pie, and feel safe and warm in a bed they could call their own ( for a short time at least ). They spent days playing in the flurries outside Snowdin or watching the pulsing glow of Waterfall’s lanterns only to rewind them and sweep the leisure time under the rug. They scoured every inch of the Librarby and wall writings to learn everything that had been recorded about the war between humans and monsters, but not much of it seemed helpful. They were wasting time, to put it simply, experimenting with their limited ability to leap through its stream and taking a sort of childish delight in what seemed to be a great big secret all their own.
Now, on the third loop of the fourth day since their fall to the Underground, Frisk leaned their small frame against the rope-y handrail of the bridge into Snowdin, finishing off a Nice Cream. They’d been prone to backtracking to areas already seen, as well, but the sense that it was likely time to move on and see another ending to it all hung over their thoughts as they looked out over the pine forest far below.