Six months after nearly losing their lives to a serial killer in New York City, FBI Special Agents Ty Grady and Zane Garrett are suffering through something almost as frightening: the motony of desk duty. When they're ordered to take a vacation for the good of everyone's sanity, Ty bites the bullet and takes Zane home with him to West Virginia, hoping the peace and quiet of the mountains will give them the chance to explore the explosive attraction they've so far been unable to reconcile with their professional partnership. Ty and Zane, along with Ty's father and brother, head up into the Appalachian mountains for a nice, relaxing hike deep into the woods... where one will hear them scream. They find themselves facing danger from all directions: unpredictable weather, the unrelenting mountains, wild animals, fellow hikers with thing to lose, and the most terrifying challenge of all. Each other.