Back to the Future Part III (1990)

This movie picks up where the last one left off--Marty stuck in 1955 after watching the Delorean vanish after being struck by lightning with Doc in it. But moments after, he got a letter from Doc that tells him he was sent to 1885. But the Delorean was damaged and he can't repair it. So he placed it somewhere where he hopes Marty can find it in 1955 and hopefully his younger version can repair it so that Marty can return to 1985. So he goes to the 1955 Doc Brown and tells him about what happened and shows him the letter. So they set out to find the Delorean and do which was hidden near a cemetery. After finding the Delorean, Marty and Doc were about to leave when they find a tombstone with Doc's name on it that says he was killed a few days after he sent the letter and that he was killed by someone named Buford Tannen. Marty and Doc go to the library and learn that Tannen was a crazed gunman and a photo of Doc in 1885. Marty then decides to go back to 1885 to save Doc. Upon arriving, the Delorean gets damaged and the gas tank is leaking. Marty then goes to town to look for Doc. But along the way he meets Tannen and gets on his bad side. Doc saves him and Tannen threatens Doc. Marty then shows Doc the photo of his tombstone. That's when Marty and Doc get ready to leave. But when Marty tells him about the gas tank, Doc tells him, without gas they can't get the Delorean up to 88 miles per hour to activate the time circuits. So they scurry to find a way to get it up to that speed before Doc gets shot. They think they found one which they plan to implement on the day he gets shot. Doc then meets Clara Clayton, the town's new schoolteacher and is smitten with her. That's when he has second thoughts about leaving. When Tannen tries to make a move on Doc, Marty stops him that's when Tannen challenges Marty to a gunfight. Marty initially declines but when Tannen calls him a coward, Marty accepts. Doc and Marty's ancestor tries to convince him he's making a mistake.