In the new MLP:FIM, Luna comes to ruin Nightmare Night by turning it into a boring feast like the Grand Galloping Gala. But Pinkie Pie is not about to let that happen, even if means the end of Nightmare Night FOREVER.
You don't actually know that's the plot until near the end, though. n.n You think Pinkie's being insanely stupid and screaming and running away out of fear, but she's really just trying to save the kids from Luna's attempts not to be scary, since the whole POINT is to be scared. Especially for the kids.
I liked the episode a lot.