Horrible things move through the shadows of our world—bloodsuckers, Full Bloods and mongrel beasts, shapeshifters and minor freaks. For centuries creature hunters known as Skinners have protected humankind. But who protects the Skinners . . . from madness?

Unbeknownst to the human population, a pestilence is raging through an unseen community of low-level monstrosities. What seems, at first glance, a boon for the mortal cause has horrific connotations—as the Skinner team of Cole Warnecki and Paige Strobel races across the Midwest to uncover the shocking secret of the “Mud Flu.” For a nightmare of destruction and blood sacrifice is looming—one born of an unholy meeting nearly two centuries ago—that will pit man against beast, and Skinner against Skinner.