The Ending Of Back To The Future Part II Explained

Back to the Future is the rare summer blockbuster that's also considered one of the best movies of all time — and maybe even the best sci-fi movie of all time. Looking back, it's easy to see why it was so successful: It's built on the friendship between its two charismatic stars, Michael J. Fox and Christopher Lloyd. It has a fast-paced script that manages to convey convoluted time travel concepts in a way that everyone can understand while also being full of laughs. And above all, as far-fetched as the story is, it still touches on themes that all of us can relate to.

Movie sequels almost never live up to their predecessors, but Back to the Future Part II came closer than most when it premiered in 1989. Doc Brown and Marty McFly have changed since the events of the first film. In Back to the Future, Doc and Marty had just discovered time travel and were figuring out how it actually worked in reality. When Marty traveled back to 1955, one of their first discoveries was that changing events in the past could drastically alter the present, even causing Marty himself never to be born. But in Back to the Future Part II, Doc and Marty have a better understanding of time travel. This time, the story is about learning to use time travel responsibly.

The big crisis in Back to the Future Part II is that Hill Valley's worst bully, Biff Tannen, gets his hands on a sports almanac from 2015 and takes it back to 1955, where he uses it to bet on sports and become one of the richest people in the country. But this scheme was never Biff's idea; it was Marty who first spotted the almanac in 2015, and it was Marty who bought it hoping to cash in. Doc stopped Marty from using the almanac, but not before it fell into Biff's hands. Biff didn't hesitate to cash in, and by 1985, he was a billionaire.

Giving billions of dollars to a bully like Biff is bad enough by itself, but Marty also has to witness the consequences. In the alternate version of 1985, Biff's casino has sucked Hill Valley dry, and the entire town is under his thumb. Marty's family suffers the most — Biff has murdered Marty's father George and forced his mother Lorraine to marry him — but now the entire town is suffering, too. Marty spends the rest of the movie cleaning up the mess, which never would have happened were it not for his initial greed. 

But Marty's most terrifying moment is actually earlier in the film.

When Marty first travels to 2015, before Biff has stolen the almanac, he meets a middle-aged version of himself, who's suffering from the consequences of another bad decision. In 1985, Marty got into a drag race that ended with a major car accident. This stopped him from pursuing a music career. In 2015, middle-aged Marty is a miserable corporate drone, and when his business partner ropes him into a shady scheme, he loses his job. It's another shortcut that backfires on him, just like the sports almanac scheme would later. Luckily for Marty, he still has a time machine that lets him go back and correct his mistakes.

The first Back to the Future is an all-time great film, but Marty arguably undergoes the most personal growth in the sequel ... at least until Back to the Future Part III, when he becomes a cowboy.