What happens when the world of Equestria is introduced to a terror that could in fact destroy all of pony-kind? S.P.A.R.C (Safety Prioritization And Rescue Control) finds out when they are dispatched to the Canterlot mountains; in those mountains, a horror that no-pony should ever face. For so long, Zombie ponies have just been a old pony tale, but is Equestria prepared for this type of threat?

Big Macintosh, one of the highest ranking members of S.P.A.R.C is caught right in the middle of a conspiracy. This conspiracy is much larger than the princess herself, and indeed if the evil contained in those mountains ever escaped, it would mean certain doom to the peaceful world of Equestria.