This is the essential "historical recollection" that sets the stage for the full series of terrifying events in the book (and potentially any expanded "mountain series" if it's part of a connected narrative or planned sequels). "The sleepy town is in for a terrorizing awakening as the townspeople are pitched into a horrifying chain of events."
"This chain of events will strike terror into the very soul of the town with its ghastly life-altering changes."