Long ago, a village in Equestria was struck with a terrible plague. The ponies fell deathly ill in mere days, coughing phlegm and blood as their muscles shriveled; crops withered and died as a poisonous odor permeated the air. And if that weren't enough, strange bellowings and roars could be heard from the distant woods.

A plea for help summoned two of the Pillars of Equestria: the Mage Meadowbrook, the Mystical Mask who could cure any sickness, and the mighty Rockhoof, mover of mountains and tamer of monsters.

When they respond, the two heroes quickly determine that this is no ordinary disease. Following the trail, they find the true source of the plague, and soon must battle for not just the villagers' lives, but their own...