Back to the Future Part II is a 1989 American science fiction comedy adventure film and the second installment of the Back to the Future trilogy. It was directed by Robert Zemeckis, who directed all three films, scripted by Bob Gale, and stars Michael J. Fox, Christopher Lloyd, Thomas F. Wilson and Lea Thompson. The plot of Part II picks up where the original film left off. 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 in jail. 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.