Twilight receives a letter from Princess Celestia one night, instructing her to complete the included spell left unfinished by Star Swirl the Bearded. Curious, she casts the spell as an experiment. Just to see what it does, really. She goes to sleep disappointed; it's hardly a spell at all, just a little shifting of the magical currents inside her. It definitely needs work.

The next day, Ponyville is in chaos. No, Equestria is in chaos. Everypony's cutie marks are different. Their destinies are different. And they are not handling this change very well.

As for Twilight? Well, her cutie mark isn't exactly different.

It's gone.

A simple re-imagining of the Season 3 finale (in three parts or "episodes"), with a simple goal: To maintain the strong characters and nuanced morality that defined My Little Pony: FiM at its peak.