It was supposed to be Trixie's vacation, a soul searching trip to Ponyville. Instead she found herself in a town full of crazy, enthralled ponies, the result of Twilight becoming corrupted by a mysterious amulet.
Managing to escape conversion, she set out to form a resistance movement. It's off to a great start. She already has Fluttershy.
(Genre-deviating sequel to Hostile Takeover)