Nightmare Moon. It was, is, and always will be a name that invokes fear and terror in the hearts of all ponies. But for Princess Luna, it was, is, and always will be a terrible stain on her past. Unable to bear her guilt, and haunted by the memory of being Nightmare Moon, discover the terrible self-inflicted punishment Luna endures, and what ultimately lead her to creating the creature that houses her personal nightmare: The Tantibus.