Back to the Future Part II (1989)

In this zany sequel, time-traveling duo Marty McFly (Michael J. Fox) and Dr. Emmett Brown (Christopher Lloyd) return from saving Marty's future son from disaster, only to discover their own time transformed. In this nightmarish version of Hill Valley, Marty's father has been murdered and Biff Tannen, Marty's nemesis, has profited. After uncovering the secret to Biff's success -- a sports almanac from the future -- Marty and the Doc embark on a quest to repair the space-time continuum.