A dozen unicorns have been drawn towards a mysterious mansion on a hill on the outskirts of Ponyville. Tasked with finding out why, Twilight and her friends enter themselves, only to fall victim to the spirit within, who can control every aspect of the house.

Then, influenced by the spirit, one of them becomes a traitor to serve his nefarious purposes. How long can the ponies hold out before they are all destroyed?

Written for the Change of Pace contest by HapHazred