A team of U.S. Marshals are charged with protecting mob-trial witness Cate Vale and her introspective teenage daughter, Alice; relocating them to an isolated compound high in the Californian Rockies. The location appears secure; outfitted specifically for witness protection, yet its past is steeped in mystery and violence - a sanctuary that rests at the heart of an unspeakable horror that is about to descend upon the world.