Back to the Future III (1990) - 20 anniv edition

Hill Valley Courthouse, November 12, 1955. Startled by Marty's improbable arrival after the severe electrical thunderstorm in Back to the Future Part II (1989), Doc is in for another surprise when he discovers that the violent electromagnetic blast has accidentally sent 1985 Emmett back to January 1, 1885. As a result, with the DeLorean time machine in terrible shape, Marty leaps seven decades back to save Doc from a fatal encounter with trigger-happy outlaw Buford "Mad Dog" Tannen. But no one died of old age in the Wild West. And as Doc and the flamboyant stranger from the sky struggle to restore the delicate time/space continuum, sweet romantic entanglements further complicate things. However, the plan is to patch up the dusty DeLorean and return to 1985 in one piece. But using only 1885 Hill Valley's primitive means, how can the intrepid time-travellers get back to the future one last time?