Back to the Future Part 3
When Marty McFly (Michael J. Fox) receives the hundred-year-old telegram from Doc Brown (Christopher Lloyd) at the end of Back to the Future Part 2, telling him that he’s alive and well in the Old West, it also has another tidbit of information – that he’s hidden the time machine in an old cave outside of town. But Marty needs some help getting it running.
So he returns to town just in time to see himself leave to go back to the future for the first time, and he surprises the original Doc (the 1955 Doc), and tells him all about what’s happening. Or at least, enough so that he doesn’t know anything about his future, because Marty doesn’t know that Doc has read the note that he gave him, telling him about the terrorists in the original Back to the Future.
With Doc on board, he gets some help getting the DeLorean back up and running, and using the Mr. Fusion to generate the power, Marty heads back to 1885 to see if he can rescue Doc and head back to 1985 – which will hopefully be the same as they left it!