Marty heads back to the old west to rescue Doc Brown but finds himself trapped when the DeLorean is damaged.
See also: Part I & Part II.
Marty runs into town and approaches Doc Brown who just sent the other version of Marty back to the future.
Marty returns to Doc Brown's house with him after receiving the letter from the past.
After sleeping for awhile, Marty and the Doc discuss the letter from the past.
The Doc gets Marty set up to travel back in time at a local drive-in theatre, and after Marty arrives in the past he is faced with a group of Indians riding towards him.
Marty falls down a hillside and is knocked out by when he hits the bottom.
Marty walks down the train tracks and arrives in the small town of Hill Valley.
Doc and Marty attempt to get the DeLorean up to speed using a team of horses.
Doc Brown and Marty look at the ravine with the incomplete bridge.
Marty and Doc chat while riding beside a stream.
Marty and Doc Brown load the DeLorean onto the railroad spur.
Mad Dog Tannen wakes his crew to take them into town to kill the Doc.
The Doc tries to get Clara Clayton to the front of the train while Marty rides in the DeLorean.
Doc and Marty jump atop the train and run its length to the engine.
Marty arrives back in 1985 in the DeLorean which is promptly destroyed by an oncoming train.
Marty runs through the entrance of his neighborhood.
Marty heads back to his house and picks up his fancy pickup truck.
Marty arrives back in 1985 and wakes up Jennifer from where he left her at her house.
Marty is driving with Jennifer in his new truck when a group of kids challenge him to a race.