We know Twilight Sparkle as the silly little mare who didn't have any friends until she was sent to Ponyville by Princess Celestia. However, the rest of Equestria knows Twilight Sparkle as poor number 107497, a number even foals are taught to be wary of. The filly was perfectly fine, until one last taunt pushed her over the edge, into her own imagination, where she made friends; each friend a part of her mind.
Five years later, as Princess Celestia sits with her comatose student, aforementioned student moves. Both in the physical world, and slowly from her dream world as well.
Rated Teen because... well... I'm not sure, it just needs a Teen tag.