While researching a book on serial killings, writer Brian Kessler (David Duchovny) and his girlfriend, Carrie Laughlin (Michelle Forbes), travel cross-country to the murder sites and unwittingly stumble upon strangers who know the subject firsthand. A pair of hitchhikers (Brad Pitt and Juliette Lewis) offer to share expenses for the trip, but Kessler doesn't realize just how close he is to his subject -- even as bodies pile up behind them.