Toward the end of the Korean War, young Pvt. Roy Loomis (Robert Redford) joins the soldiers at the front line. In Loomis' new infantry company, he encounters Pvt. Raymond Endore (John Saxon), a man with an intense desire to kill. Endore undertakes lone nightly reconnaissance missions, where he's made a habit of cutting suspected enemies' throats. The company's leader (Charles Aidman) does little to stop this behavior -- and when the armistice is announced, Endore has no intention of leaving.