Is nature striking back... or is a serial killer on the loose? It's an idyllic late-summer day in Saddlestring, Wyoming, and Game Warden Joe Pickett is fly-fishing with his two daughters when he stumbles upon the mutilated body of a moose. Whatever attacked the animal was ruthless: half the animal's face has been sliced away.

Shaken by the sight, Joe starts to investigate what he hopes in an isolated incident. Soon, more animals are attacked. Local authorities are quick to label the rash of mutilations as the work of a grizzly bear, but Joe suspects something far more sinister.

And when the similarly disfigured bodies of two men are found, his worst fears are confirmed: a modern-day Jack the Ripper is on the loose - and the killings have just begun