In 1955, having just seen Doctor Brown (Christopher Lloyd) disappear into the past in his DeLorean time-machine. Marty McFly (Michal J. Fox) receives a letter from Doc written in 1885. He goes to the Doc in 1955 and together they repair the DeLorean so Marty can go to 1885, but there is a tombstone with Doc’s name on it, saying that he was shot by Biff Tannen’s ancestor Buford “Mad Dog” Tannen (Thomas F. Wilson, both of them).
Marty travels back to 1885 to save Doc and arrives in the middle of a Cavalry pursuit of indigenous warriors. The car’s fuel line is broken. He is chased by a bear, knocked out, and found by his Irish great-great-grandparents Seamus and Maggie McFly (Michael J. Fox and Lea Thompson). The next morning, he arrives in Hill Valley but runs into Buford and his gang. They try to lynch him, but Doc appears and rescues him with his hand-built rifle. After learning that he will die in six days, Doc agrees to leave, but there is no such thing as gasoline and the DeLorean cannot reach 88 mph to start up the flux capacitor. He decides to get a steam locomotive to do the job.
Inspecting a rail spur, Doc saves Clara Clayton (Mary Steenburgen) from falling into a ravine on a runaway wagon. They fall in love immediately. Marty stops Buford from shooting Doc but Buford challenges him to a showdown in two days. Thinking he will be gone by then, Marty accepts the challenge. Doc visits Clara and tells her the truth about his origin and she does not believe him. In fact, she is insulted. Despondent, he drinks too much (one shot of whisky) and passes out. Buford arrives to deal with Marty, but Marty has seen his own tombstone and refuses. Marty pretends to be shot and knocks Buford into a manure wagon. Buford is arrested for a recent crime.
On the train for San Francisco, Clara learns how heartbroken Doc is and runs back to town. Finding proof of the time-machine in his shop, she heads for the train. Doc and Marty have stolen a locomotive and are pushing the DeLorean along the spur line faster and faster, carried along by the rapid cutting and Silvestri’s driving music. Clara jumps onto the locomotive and hangs there. Marty, in the DeLorean, passes his hoverboard to Doc and he saves Clara, getting away just as the locomotive tumbles off the unfinished bridge and vanishes.
The time machine lands on the finished tracks in 1985 and Marty gets out just before it is smashed to pieces by a freight train. He is reunited with Jennifer. As they examine the remains of the DeLorean, a steam-punk locomotive appears, run by Doc, Clara, and their children, Jules and Verne. Doc gives Marty a photo of them in front of the town hall clock as it is being built in 1885. Waving goodbye, Doc and his family lift the train into the air, turn around, and vanish into Time.
This was the third installment of the Back to the Future Trilogy, directed by Robert Zemeckis. It received the best reviews of the three films, and the adoration of fans. Mary Steenburgen was reluctant to take on the role, which was in fact written with her in mind, until her children insisted. She tore a ligament in her foot dancing a hoedown. Old-timers Pat Buttram, Harry Carey Jr., and Dub Taylor appeared for Western movie street-cred.
Practically every stuntman who could ride a horse wanted to be in it. Alan Silvestri’s music was directed by Zemeckis as if it was a character in the movie. Industrial Light and Magic did the effects. Michael J. Fox was rendered unconscious in the hanging scene. Clint Eastwood was tickled by his name being mentioned in the film. The 1885 Hill Valley set was the same one used in Clint Eastwood’s Pale Rider in 1985, which was knocked off the number one slot by Back to the Future.
ZZ Top was playing the town band when the camera broke, and they entertained the cast and crew while it was fixed. Two hours later, Zemeckis pointed out that the camera had been fixed, but he hadn’t felt like breaking up the party. Marty knocked the gun out of Mad Dog’s hand with a Frisbie’s pie plate. The wheels of a DeLorean are precisely wide enough to run on a railroad track. Mary Steenburgen said of her falling in love with a man out of Time that it was strange to play the same scene in two different movies. In Time After Time, she is from the 20th Century and falls in love with a man from the 19th, and in this movie it was the other way around. Steenburgen’s birthday is the same as Jules Verne. The character of Clara Clayton was named in honor of Clara Clemons, Mark Twain’s daughter, who was saved from being dragged off a cliff in a runaway horse-drawn sleigh by her future husband.