Wendy Nugent, sheriff of Harrison County, Nebraska, grows suspicious when a government lab springs up on an abandoned farmstead near her own farm in the Blue River Valley, in the middle of nowhere. Despite being reassured by a colonel from the Pentagon, a representative of Homeland Security, and a Princeton scientist that it is simply a federal livestock research lab, she doesn't buy it. Nugent tries to investigate, only to be rebuffed by scientist Mark Sterns, with whom she begins a romantic relationship.
Something beyond the normal research is obviously occurring in that compound, which sports its own Marine guards and security fences. She is kept in the dark until a powerful storm destroys the lab and unleashes a real terror that threatens her once-quiet county.