This is a true? story about a very religious, vegan, pacifist named Desmond Doss [Andrew Garfield], who joins the US Army during WW2, but refuses to ever hold a riffle, and insists on taking the day off every Saturday to pray. His Sergeant [Vince Vaughn] and Captain [Sam Worthington] try hard to make his time in the boot camp as unpleasant as possible, think "Full Metal Jacket" (1987), and try to get him to quit. When that fails, they conduct a court-martial instead and try to have him jailed instead.
I really don't like the main character of this movie. Fair enough that he demands to serve his country, but if he won't pick up a riffle in the middle of a raging war then he shouldn't be allowed to be there. He is a danger to all of his friends and the movie should have ended right there with him going to jail for acting like an idiot. It doesn't.
The second half of the movie has old-style ultra brutal war scenes, where the Americans are trying to take some Japanese positions in the Battle of Okinawa. Apparently Desmond is some kind of Jesus figure, because he manages to save a lot of his wounded friends against impossible odds.
All this might sound rather terrible, and it could have been, if Mel Gibson wasn't such an awesome director. The first half is a bit slow at home with the alcoholic and violent father [Hugo Weaving] and Desmond getting himself a hot girlfriend [Teresa Palmer], but the second half makes up for much of it. It is a bit sentimental at times, but Mel Gibson knows how to make movies that work, and this is no exception. The battle scenes are very intense and look impressive on the big screen with the big sound.