A piece of the Hearth's Warming tale that no one was ever told.
Snowfall Frost had been given an assignment from the spirits. That nopony should ever denounce Hearth's Warming again, or she and that same pony would face a fate worse than death.
When Snowfall learns that a new pony preaching humbug has moved into town, she desperately begins to save her.
Or neither of them would reach Hearth Warming Morning.

(The idea of a horror based Hearth's Warming story comes from the idea of "Violent Night.")

(Chapter one contains a very similar scene to the opening of the movie "Drag Me To Hell."
If that discomforts you, don't read this one :)