Back to the Future Part III is a 1990 American science fiction Western film. It is 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 takes place immediately after the events of 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 (Lloyd), trapped in 1885, was killed by Biff Tannen's great-grandfather Buford.