Jim and Brad make their annual hunting trip to the desert, but this year everything is different: Their third partner, Paul, has died in an accident and they've taken his nephew, Ray, along in his place. When they arrive, though, there's not a single animal to be found, only a grizzled old-timer who joins them. When they meet two female campers, they all begin to behave aggressively, unable to resist their animal urges. The next morning the women have disappeared, but the strange moods and behaviors persist and change in ominous ways. Something has them in its grip and it has total control over them...