A New Reset

We all know the many endless resets undertale has gone through. The mercy route and the killer route, but no matter what reset Sans always remembers. Every death, every mercy, every tear that drops. He has seen it all, but what if another human has seen everything too.
Milost, also known as Mimi has also seen every reset. The only difference being is that she sees the aftermath of what happens in the underground. She either sees Frisk coming out with monsters claiming that they are there friends or coming out of the tunnel covered in dust, with a sharp toy knife. Milost has been noticing something strange has been happening within the last few resets, Frisk has been coming out with enormous amounts of dust on them each time. Milost, unhappy with these ending decides to follow Frisk into the underground and figure out why this keeps happening.