Twilight Sparkle believes that, if Equestria wanted to avoid another incident like Shining Armor's almost marriage to the Changeling Queen, they must learn more about.. well, just about everything. She leaves her friends behind and goes on a journey to discover things that nopony in Equestria knows.. and ends up finding a spell with some pretty interesting results. This spell allows the user to change their appearance, or the appearance of any pony with an illusion!