Hogwarts School for Witches, Wizards, and now... Unicorns, apparently?

Sweetie Belle wants to use magic. So, who else but the wielder of the Element of Magic, Twilight Sparkle? Thing is, nothing is ever as it seems in Ponyville, and turns out Sweetie has a much larger destiny than anypony thought the little filly had.

During an adventure to the Everfree Forest to earn their Cutie Marks, the Cutie Mark Crusaders get gravely injured and worse. What is the result of their mindless actions?