A murderer goes around Ponyville, during Nightmare night season and is killing ponies also they are leaving pumpkins at the crime scene. Some pumpkins also left behind notes. Will the Mane 6 find who is behind this? Will the ponies be able to celebrate Nightmare Night without worrying about the killer?

It's also kinda based on the movie, The snowman, I never saw the movie but I know the main story.