Back to the Future Part III (1990)

Synopsis
The final installment in the Back to the Future trilogy picks up where the second film left off, but it casts off the dizzying time travel of the first two films for mostly routine comedy set in the Old West. Marty McFly (Michael J. Fox) receives a 70-year-old letter from his inventor friend, Doc Brown (Christopher Lloyd), who tells Marty that he has retreated a century in time to live out a relatively quiet life in the Old West. Doc Brown reveals that he hid his DeLorean car/time machine in an abandoned mine outside town, and when Marty does some research and discovers that the Doc died shortly after writing the letter, he decides to find the car, travel back in time, and warn the Doc about his demise. Meanwhile, the Doc, who has fallen in love with a local woman (Mary Steenburgen), realizes he can't hide in the past from the problems he has caused to the time flow in the previous two adventures. He reluctantly decides to return to the present with Marty, but first, they have to find a way to get the DeLorean up to time-travel velocity with a broken fuel line and no gasoline. ~ Don Kaye, All Movie Guide