After his eventful journey between past, present and future, Marty McFly learns from a hundred year old letter that his old friend Emmett "Doc" Brown crashed in 1880 at the wheel of his DeLorean, thus remaining a prisoner of the far west, under the threat of Buford "Hound" Tannen who has sworn to kill him. He only has five days to find Doc and bring him back alive to the present ...