John, an ex-Navy Seal, accompanies his girlfriend and her students on a weekend photography trip deep into the woods. But this educational and fun-filled weekend quickly turns into a nightmare as the group is besieged by an unspeakable evil - a horde of hideously disfigured, mutated humans with an insatiable taste for blood. As things go from bad to worse, John becomes their only hope if they are going to get out alive.