Thus reads the message received from a Nazi commander stationed in a small castle high in the remote Transylvanian Alps. And when an elite SS extermination squad is dispatched to solve the problem, the men find a something that's both powerful and terrifying. Invisible and silent, the enemy selects one victim per night, leaving the bloodless and mutilated corpses behind to terrify its future victims. Panicked, the Nazis bring in a local expert on...