Pinkie, primer part pony. Everyone loves to be with her... for short periods of time.

But when a certain pegasus forgoes finding Pinkie and Rarity after being knocked off the chase carriage while trying to talk with Applejack, Rarity will find Pinkie herself isn't just mad, but capable of dragging others into the depths of insanity with her. They will find their trip home to be less than easy, both to their physical, and mental wellbeing.