Back to the Future II (1989)

Just being back from a trip through time, Marty McFly (Michael J. Fox) and his girlfriend Jennifer (Elisabeth Shue) are taken by Doc Brown (Christpher Lloyd) to another trip through time - this time 30 years into the future. Doc and Marty intend to get one of Marty's future kids out of big trouble. The real story starts when the three are back in time and recognize another 1985 as the one they left. They are figuring out that Biff (Thomas F. Wilson) must be responsible for this "parallel year of 1985". The reason for all seems to be a sports almanac of the year 2015 handed out to young Biff by himself (just about 60 years older) in the 1950's, him being able to win every bet and become a powerful man. So Doc and Marty need to travel back to the past and pilfer the almanac from Biff in any way...