On a desolate highway through Death Valley, a man picks up a hitchhiker, Lucindia Polonia [Phoebe Dollar], offers her a drink, and soon after she coughs violently. The liquid sends her into a fit, she stumbles from the car, and is stabbed to death by the motorist. The man, revealed to be a priest, buries Lucindia’s body and plants a crucifix over the grave. As he prays, Lucindia reappears and bludgeons him with his shovel, its silence broken by a shouted, > El Diablo!
Nearby, four college students, Eric [Hank Horner], Chris [Jonathan Gray], Monique [Beverly Lynne], and Sarah [Kiren David], from Western Pennsylvania, are on a road trip toward Redondo Beach. They spot Lucindia at a cluster of crosses and decide to pick her up. When Chris mentions that a group of their friends is also on the way to Redondo, Lucindia boasts that she tortured them to death before pulling out a gun and sexually assaulting Sarah [Kiren David]. She then tries to shoot Sarah in the crotch, but is knocked out of the car by Sarah and Eric.
The next day, Lucindia, who had just robbed, castrated, and murdered a motorist, catches up with the group and is run down, beheading and disemboweling her. On what remains of Lucindia’s body, Eric finds Chris’s brother’s cell phone and a battery pack that fits into a camcorder Sarah had unearthed in the desert. The group watches the last minutes recorded by the camera, showing Lucindia shooting all of their friends during a botched séance. Lucindia then turns to the camera and recounts the tale of a settler couple that became trapped in the valley; to save his wife (implied to be Lucindia), the husband killed himself so she could consume his flesh. His body isn’t enough to sustain her, and in her final hours the woman curses God and prays to the Devil for salvation, receiving it in exchange for a steady stream of victims.
When the video ends, Lucindia appears again and attacks Chris with a chainsaw. The students drive off, but Lucindia tails them when they run out of gas. Sarah, Eric, and Monique flee, yet are cornered by a pair of Lucindias, who murder Monique. Sarah accidentally kills Eric, then kills one of the Lucindias and is saved from the remaining one by two government operatives, who capture Sarah.
Sarah is taken to a military installation, where officials reveal that there were four equally delusional Lucindias, the result of cloning and accelerated growth experiments. The staff explain that Sarah is to become their next test subject, and as they prepare an injection, a wounded Lucindia barges in. Sarah screams, "I told you the Devil would come back!" as Lucindia opens fire with a shotgun, triggering an explosion that presumably kills her and everyone else in the room.
