Back to the Future Part II is a 1989 American science-fiction adventure comedy film directed by Robert Zemeckis and written by Bob Gale. It is the sequel to the 1985 film Back to the Future and the second installment in the Back to the Future trilogy. The film stars Michael J. Fox, Christopher Lloyd, Thomas F. Wilson and Lea Thompson and continues immediately following the original film. After repairing the damage to history done by his previous time travel adventures, Marty McFly (Fox) and his friend Dr. Emmett "Doc" Brown (Lloyd) travel to 2015 to prevent McFly's future son from ending up imprisoned. However, their presence allows Biff Tannen (Wilson) to steal Doc's DeLorean time machine and travel to 1955, where he alters history by making his younger self wealthy. More: en.wikipedia.org.