On a rainy night in the middle of nowhere, Jim Halsey and Grace Andrews exhibit some goodwill and pull over to pick up a hitchhiker. When the hitchhiker, John Ryder, eerily threatens them with a knife, Jim kicks him out of the car. The next morning, Jim and Grace are shocked when they happen upon a family that has been massacred on the side of the road. When they realize that the same hitchhiker is to blame, continuing a suspenseful cat-and-mouse chase with tragic consequences.