WWII American Army Medic Desmond T. Doss, who served during the Battle of Okinawa, refuses to kill people and becomes the first Conscientious Objector in American history to receive the Congressional Medal of Honor.
In Lynchburg, Desmond Doss and his brother Hal are raised by a dysfunctional family since their father Tom Doss is an alcoholic veteran of World War I that beats their mother Bertha. One day, Desmond almost kills Hal and his life is affected by the Commandment "Thou shalt not kill". Years later, he meets the nurse Dorothy Schutte and they fall in love with each other. Desmond, who is Seventh-day Adventist Christian and conscientious objector, decides to join the army to serve his country in World War II; however he refuses to carry or use any weapon and requests to serve as combat medic to save lives. He faces several problems during the training and but he succeeds to go to the war to participate in the Battle of Okinawa. Will he be helpful in the battle field?