.Just Back to the Future.
In 1985 Hill Valley, an inquisitive teenager named Marty McFly travels back in time in order to save his parents marriage and just maybe -- his own life.
On October 26, 1985, Emmett Brown arrives in the DeLorean time travel and persuades Marty McFly and his girlfriend, , to travel to the future with him and help their future children, with Biff Tannen witnessing their departure. They arrive on October 21, 2015, where Doc electronically knocks out Jennifer and leaves her asleep in an alley, explaining that she should not have too much knowledge of future events. He has Marty pose as his own son and lookalike Marty Jr. to refuse an offer to participate in a robbery with Biff's grandson Griff Tannen, thus saving both of Marty's children from prison.
On November 12, 1955, moments after witnessing his apparent death via lightning bolt, Marty McFly (from 1985) learns that Emmett Brown (also from 1985) was transported to 1885 and is trapped. Marty and Doc's 1955 self use the information in Doc's 1885 letter to repair the DMC DeLorean, with 1885 Doc instructing Marty to return to 1985 and leave him be. Marty spots a tombstone with Doc's name, dated six days after the letter, and learns that Doc was killed by Biff Tannen's great-grandfather, Buford. Marty takes a picture of the tombstone and travels to 1885 to save Doc.