Μύ Doc Brown (Christopher Lloyd) is stranded in the old West of 1885 - and happily. But in 1955, Marty McFly (Michael J Fox) learns that the Doc was killed by Buford "Mad Dog" Tannen - the ancestor of Marty's nemesis Biff. Going back to rescue the Doc, though, the DeLorean time machine is damaged and may not get them back to the future.
Made back to back with the cleverer Part II, this is still not as tremendous as the first movie but it is thrilling, funny and very exciting. It's also got what Part II lacked: a rousing conclusion, this time with a fairly heart-stopping train ride.
It's very easy to tell that these two films were made together because they each contain close references to one another and Part II sets up storylines for III, such as introducing us to Buford "Mad Dog" Tannen. These repeating elements would have worked better if they had been across all three movies, as this way they sometimes stand out as being obviously foreshadowing.
But there is one element that ties back across the trilogy and that's the Hill Valley clock tower that we've seen hit by lightning. In this concluding film, we get to see Marty and Doc Brown posing before the clock itself, before the tower is built, and oddly it makes the movie touching as well as exciting.
Treat the trilogy as just two movies - the original one and then Parts II and III together - and you've got what is deservedly one of the most popular double acts in cinema history.
