Port Allen, Texas is about to have a visitor: a category five hurricane named Whitney. But when the survivors crawl from the wreckage of their city, they will face horrors much worse than the storm.

They're cut off from the outside world. A mysterious disease sweeps bloody death through the remaining populace. Faceless commandos prowl the streets, shooting civilians on sight. And from the shadows, a hungry beast drags the innocent into the dark to feed.

Now, a germophobic shut-in, a homeless man, a disgraced cop, and many others must band together to discover the truth about the evil hunting them, and find a way to escape...