Intent on seeing the Cahulawassee River before it's turned into one huge lake, outdoor fanatic Lewis Medlock takes his friends on a river-rafting trip they'll never forget into the dangerous American back-country.

A group of college students accidentally see a local redneck kill his wife's lover. A deadly game of cat-and-mouse ensues, with the students trying to escape the area while the killer sets out to eliminate the witnesses who can tie him to the murder.