On a desolate country highway, two homeward-bound teens, Trish (Gina Philips) and Darry (Justin Long), are nearly run off the road by a maniac in a beat-up truck and later spot him shoving what appears to be a body down a sewer pipe. But when they stop to investigate, they discover that the grisly reality at the bottom of that pipe is far worse than they could have ever suspected, and that they are now the targets of an evil more unspeakable and unstoppable...