Back to the Future Part II(1989)

In this unconventional sequel, the time-traveling protagonists Marty McFly and Dr. Emmett Brown return following their successful intervention to prevent catastrophe for Marty's future son, only to encounter a fundamentally altered temporal landscape. Within this dystopian rendition of Hill Valley, Marty's father has been assassinated and Biff Tannen, Marty's principal antagonist, has accumulated substantial wealth. Upon discovering the mechanism underlying Biff's prosperity—a futuristic sports almanac—Marty and the Doctor undertake an expedition to restore the integrity of the space-time continuum.