This story is a sequel to The Rainbow's Surprise

On the day of Fluttershy and Rainbow Dash's wedding, Princess Celestia left Twilight a message saying that she should prepare herself if something happens. The next morning, Twilight awakens to find that all of Ponyville has succumb to a blinding fog. She must now travel a monster-filled town in search for her teacher and friends and try to return Ponyville back to the way it was.

Celestia agrees to allow Twilight to spend the night at the palace per Luna's request. But as it turns out, the two ponies have other things in mind other than a sleep-over...