The film is particularly notable for the intensity of the initial 20 minutes or so which depicts the Omaha beachhead assault. Thereafter it takes a very heavily fictionalised route built around the fact that a member of the 101st Airborne was returned to America.
warning: Wikipedia contains spoilers
The general plot of the film, as the title suggests, is a humanitarian rescue mission led by John Miller, an army captain, played by Tom Hanks to return the last surviving Ryan brother from the Normandy front line to his mother. The movie also stars Tom Sizemore, Edward Burns and Matt Damon. Many critics commented that the film seemed marred somewhat by Spielberg's propensity for sentimentalism.
Miller, as played by Hanks, conceals his erstwhile profession of schoolmaster and his background from the troops under his command; the uncovering of Miller's background becomes a sub-plot of the film in as much as the men have a pool on his origins, which he steadfastly refuses to reveal. Under intensely difficult circumstances, Miller displays a decisive and courageous manner to his soldiers - his suppressed nervousness is communicated only by his unsteady hands.
The bond between Miller and his men is forged in the beachhead assault on a German bunker, where his decisive action saved the day.
As the position consolidates, Miller is given his new assigment, to find Private Ryan, who had been parachuted in as a member of the 101st Airborne, which, as the film historically correctly asserts, was scattered widely across Normandy. Ryan is the sole surviving member of four brothers, the other three having been killed in action. The American command takes the decision to bring him back for his mother's sake.
Eventually, at the expense of a number of members of their unit, Miller and his men catch up with Ryan. They break the news of his brothers' deaths to him and tell him that he is going home. Ryan is torn in his decision but elects not to desert his strategically important post. Miller and his men protect him, and all but a few and Ryan survive a ferocious German tank assault on the bridge which they are defending. Miller is killed in the assault.
warning: do not read the next paragraph if you believe knowing the historical facts may spoil your enjoyment of the film.
The real ‘Ryan’ was Sgt. Frederick (Fritz) Niland who, with some other members of the 101st, was inadvertently dropped too far inland. They eventually made their own way back to their unit at Carentan where the Chaplain, Lt. Col. Father Francis Sampson, told Niland about the death of his three brothers. Two at Normandy and one in the Far East. Under the US War Department's Sole Survivor Policy, (brought about following the death of five Sullivan brothers serving on the same ship), Fr. Sampson arranged passage back to Britain and thereafter to his parents, Augusta and Michael Niland, in Tonawanda. There was no behind the lines Ranger rescue mission, ‘Ryan’ was not a simple private, his mother was not a widow nor is she believed to have received all three telegrams together, and, the brother believed killed in the Far East turned out to have been captured and later returned home. Fr. Francis Sampson wrote about Niland and the story of the 101st, in his 1958 book, ‘Look Out Below!’, (ISBN 1877702005).