Back to the Future Part II ends with a clever twist that sets up the third movie in the trilogy. After Marty McFly and Doc Brown fix the messed-up timeline caused by Biff Tannen getting a sports almanac from the future, they return things to normal in 1985. Marty burns the almanac in the parking lot of the high school, watching the flames destroy the book that let Biff create his evil empire of casinos and crime.https://en.wikipedia.org/wiki/Back_to_the_Future_Part_II This act wipes out the bad future where Marty’s family was poor and broken, restoring the good 1985 they know.
Just as Doc arrives in the flying DeLorean to pick up Marty, lightning strikes the car right above them. The time machine vanishes in a flash, leaving Marty stunned on the ground.https://en.wikipedia.org/wiki/Back_to_the_Future_Part_II Doc is gone, zapped to who knows where. Marty thinks his friend is lost forever.
Seconds later, a Western Union delivery guy shows up on a bike. He hands Marty a letter from Doc, dated 70 years in the future. The letter explains that the lightning sent the DeLorean back to 1885. Doc is stuck in the Old West, but he’s fine and asks Marty not to come rescue him because of time travel dangers. Instead, Doc wants Marty to destroy the time machine so no one else finds it.https://www.imdb.com/title/tt0096874/news/https://en.wikipedia.org/wiki/Back_to_the_Future_Part_II
Marty races off to find the 1955 version of Doc Brown, the one who helped him in the first movie. He bursts into the Hill Valley town square just as 1955 Doc has sent the original Marty back home. Seeing this new Marty appear out of nowhere, 1955 Doc faints in shock. The screen fades to black on that funny cliffhanger, teasing the adventure in 1885 that kicks off Back to the Future Part III.
This ending ties the whole story together neatly. It shows how time travel creates loops and surprises, like Doc planning ahead from the past to send that letter through Western Union. Fans love how it fixes the timeline mess from Biff while opening the door to cowboys and trains.https://www.imdb.com/title/tt0096874/news/
Sources
https://en.wikipedia.org/wiki/Back_to_the_Future_Part_II
https://www.imdb.com/title/tt0096874/news/
