Back to the Future Part III

Back to the Future Part III is a 1990 American comic science fictionWestern film, and the third and final installment of the Back to the Future trilogy. The film was directed by Robert Zemeckis, and starred Michael J. Fox, Christopher Lloyd, Mary Steenburgen, Thomas F. Wilson and Lea Thompson. The film continues immediately following Back to the Future Part II. While stranded in 1955 during his time travel adventures, Marty McFly Fox discovers that his friend Dr. Emmett Doc Brown, trapped in 1885, was killed by Biff Tannens greatgrandfather Buford. Marty decides to travel to 1885 to rescue Doc.

On November 12, 1955, Marty McFly discovers that his friend, Dr. Emmett Brown, had become trapped in 1885. Marty, with the 1955 Doc, uses the information in Docs 1885 letter to locate and repair the DeLorean. He spots a tombstone with Docs name, dated six days after the letter. Learning that Doc was killed by Biff Tannens greatgrandfather, Buford Mad Dog Tannen, Marty travels back to 1885 to save Doc.Marty arrives on September 2, 1885, in the middle of a United States Cavalry pursuit of Indians. When the fuel line is torn, Marty hides the car in a cave and walk to Hill Valley. He meets his Irishborn greatgreatgrandparents, Seamus and Maggie McFly, and runs afoul of Buford and his gang. Buford tries to hang Marty, but Doc saves him. Doc agrees to leave 1885, but because commercial gasoline is not yet available, the DeLorean cannot reach 88 miles per hour under its own power. ........

Source: Wikipedia