Fluttershy and Twilight have caught a disease which regress them into foals

 It was a normal happy day in Ponyville, as all went on there way. Twilight was especially happy today she was going to help Applejack, when she stumbled across a find that would change the face of Equestria for all time.

Discord returns and the first place he visits is ponyville,
Turning Fluttershy into a filly. With rainbow dash left to take care of the filly.
But discord isn't done just yet.