Nightmare Moon has been running around Ponyville doing unthinkable acts! She's been... been helping ponies and doing charitable work! Hold on a second, that's not bad at all? Why is the evil NIghtmare Moon being so nice? What? Nopony told her she's the villian? Well gee, somepony should go do that, shouldn't they?
In case it wasn't slightly obvious, Nightmare Moon is doing things that typically aren't expected of a villian, and when Twilight Sparkle inquires as to why she's so nice, it shocks Nightmare to learn that she's the villian. Seeing no other option, she immediately sets out to rectify this situation. This is a comedy with darker elements including, but not limited to, kitten cruelty, royal beatdowns on the eldery, orphan terrorizing, property damage, and the ever present etc.