Celestia's personal student has a rather strange ability; at least once a week, she dreams of a quiet, somber wood. It has always been a peaceful place for her, a sleeping sanctuary for peace and reflection. Under this moon, however, the peace will be broken, for on this night something else stalks the silent trees with her, and it has a message that only she can deliver.

Edit: Winning Entry of Contest 2: The Sequel in the Nightmare Moon is the Best Pony group!