Marty and Doc are at it again as the time-traveling duo head to 2015 to nip some McFly family woes in the bud. But things go awry thanks to bully Biff Tannen and a pesky sports almanac. In a last-ditch attempt to set things straight, Marty finds himself bound for 1955 and face to face with his teenage parents -- again.
Back to the Future Part II is a 1989 American science fiction film directed by Robert Zemeckis from a screenplay by Bob Gale; both wrote the story. It is a sequel to the 1985 film Back to the Future and the second installment in the Back to the Future franchise. The film stars Michael J. Fox, Christopher Lloyd, Lea Thompson and Thomas F. Wilson, with Elisabeth Shue and Jeffrey Weissman in supporting roles. It follows Marty McFly (Fox) and his friend Doctor Emmett "Doc" Brown (Lloyd) as they travel from 1985 to 2015 to prevent the former's son from tarnishing their family's future. When their arch-nemesis Biff Tannen (Wilson) steals the DeLorean time machine and uses it to alter history for his benefit, the duo must return to 1955 to set things right.