Something frightening is happening in the mountain community of Mason County, Virginia. Pets are vanishing mysteriously and "Missing Dog" posters cover the waiting room walls at Dr. Rachel Goddard's veterinary clinic. A pack of feral canines roams at night, attacking livestock in a desperate search for food.

Then prominent physician Gordon Hall is found dead in his yard, his throat ripped open. Sheriff's Department investigator Tom Bridger believes the killing was premeditated murder using a trained attack dog as the weapon. He also suspects it is connected to the resurgence of an old problem: illegal dog fighting. But Dr. Hall's son insists the feral pack killed his father, and he organizes a group of men to find and shoot the animals.

Rachel and her friend Holly Turner make enemies by trying to rescue the dogs and move them to the sanctuary Holly has created. Tom, in love with Rachel and worried about her safety, must divide his time between the escalating controversy, shutting down the dog-fighting operation (if he can locate it), and hunting for Gordon Hall's killer....