Some young friends are on a road trip through remote, desert areas of California. Diana is searching for her brother, Christopher, missing for six years. With her are Eric, her boyfriend, and her cousin, Tommy, plus her best friend, Julie and Julie's boyfriend, Bill. They find the isolated village where Christopher disappeared, but the people in town make them leave. Afterward, they follow a suspicious-looking stranger to a cave nearby. Inside the cavern, a shadowed, wolf-like monster attacks them, and Tommy is seriously hurt. They then look for a doctor in town. However, instead of helping, the villagers kidnap them for a demonic ritual. Diana and the others have to face these horrors, along with the darkness within themselves. Finally, Diana must battle for survival and to keep this evil from engulfing everyone.