Speed and Back to the Future are great!
And, Yoshi, there are 3 parts; each makes up a different movie.
Time machine invented(out of a Delorean). Makes mom and dad not marry, and then fixes things.
Goes to the future(year 2015[hahaha,only 3 years away]) and keeps Marty's son from going to jail. In the process, the guy Marty made look bad in the first part finds the Delorean and uses it to get rich. Marty and Doc find out and fix the problem.
Doc accidentally goes to the year 1889 instead of 1989 when returning to the past in part II. Mary is left in 1975, and finds Doc's grave and the Delorean. He uses the Delorean to go to 1889 to save Doc. While in 1889, Doc got married and had a few kids, and Mary ends up in 1989 without them. In the end, Doc's family uses a train time machine to see the rest of time. The Delorean is dead, by the way.
"Every puzzle has an answer." - Professor Layton
December 17, 2012 - MegaMan 25th Anniversary
Member of Memefefe's Squad