In preperation for her friend's upcoming wedding, Rarity journeys to the ancestral home of the De'Lis- -with Sweetie Belle in tow- -intent on creating a set of spectacular dresses for the occasion.

Shortly after arrival, though, Sweetie Belle begins to fall ill with a strange sickness and begins to realize that something is very wrong with Castle De'Lis. The servants are hiding something, and something strange is stalking the halls- -and the inhabitants within them.