Back to the Future Part II is fiction.
Back to the Future Part II is a 1989 American science-fiction adventure comedy film directed by Robert Zemeckis and written by Bob Gale . 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 . Biff Howard Tannen is a fictional character in the Back to the Future trilogy . Martin `` Marty '' Seamus McFly is a fictional character and the main protagonist of the Back to the Future trilogy .