After glowing spots of blue light suddenly appear on the ground in the Northwest, circles of crop vanish and livestock inexplicably die.
In order to explain the bizarre and frightening events, retired University of Nebraska biology professor Joe Callen is put in charge of the field investigation. Insect husks are found beneath the animal carcasses, but he is unable to explain their unusual nature. Even stranger, a man who had been exposed to the blue light dies of apparent starvation. Terry Leggett, also exposed to the light and befriended by Joe, seems doomed to a similar fate. When a way is found to keep Terry alive, Joe is unprepared for the consequences.
Later, as a search begins for a voracious predator that has attacked the small town of Monarch, Montana, Joe must make a life-or-death decision as he watches the terrifying image of Leggett outside his window.