Back to the Future Part III

Clara (Mary Steenburgen) hears that Doc (Christopher Lloyd) was upset about breaking up with her, and realizes he actually loved her. She rushes to catch the train that Doc and Marty (Michael J. Fox) are using to push the DeLorean up to 88 mph, and propel them back to 1985. She boards the train but cannot reach the front and is in danger of going off the unfinished bridge with the rest of the train. Doc saves Clara using the hoverboard and glides off with her rather than return to 1985 with Marty. When Marty arrives in 1985, a train destroys the DeLorean as Doc had wanted. Marty finds Jennifer (Elizabeth Shue) and avoids getting into the car crash that had ruined his life in Part II's 2015 storyline. The two of them then meet up with Doc, who has returned to 1985 with Clara and his two sons (Jules and Verne) using a new time machine built from a steam engine.
Thanks, Robert F. and BudMann9!