Strange Intruder, based on the Helen Fowler novel The Intruder, is the story of a morbid pact forged by two soldiers fighting in the Korean War. During the war, American soldier Adrian Carmichael (Donald Murphy) is wounded and dying. As he lays dying, Carmichael asks his best friend, Paul Quentin (Douglas Purdum), to do him a favor. He asks Paul to avenge his wife's infidelity by murdering their young children. The audience is then transported back to the United States as Quentin tries to adjust to civilian life with the burden of fulfilling his friend's dying wish on his mind. He travels to see Carmichael's surviving family. Quentin meets Carmichael's widow, Alice (Ida Lupino), and finds her distraught over her ill treatment of her husband. Further, the children, whom Quentin is to murder, are still away at boarding school. Strange Intruder is a suspenseful psychological thriller that tackles the ravages of war at home and abroad.