This film is based on a true story about a young medic of the US army described as a "conscientious objector" meaning that it is against his principles to wield a weapon or kill another person. The character Desmond Doss ( Andrew Garfield) joins the Army and during the training shocks his superiors and colleagues when he refuses to hold a gun.This makes him highly unpopular and creates a discipline problem. He is asked to discontinue training but on his refusal he is put up for a court martial. His father who is an ex Army man then brings up a technical point where such category of soldiers can be allowed for soldier training. The charges are then dismissed and Desmond becomes a trained medic. There is a back story about his traumatic family life where his father was an alcholic and wife beater and Desmond in one violent confrontation with his father almost shoots him. He then vows that he will not touch any weapon and follows the biblical dictum "Thou shalt not kill". Desmond is a part of a group which plunges into thick of the battle and after a long and bloody battle he bravely rescues 75 injured soldiers by dragging them over the hacksaw ridge into the hands of waiting groups of medics.This was acknowledged as supreme bravery against highly adverse operational conditions for which he was awarded with a medal of honour by the President of the United States. The movie has competent direction by Mel Gibson and the movie is impressive. Particularly noteworthy are the extended war scenes which are truly graphic with soldiers shown with mutilated bodies and dead bodies all over. Maybe these scenes are overdone with the gory details but that is Mel Gibson's speciality. Remember " The passion of the Christ." The highlight of the film is the superb acting of Andrew Garfield who has got under the skin of the character.