Although the Back to the Future trilogy is widely considered to be better left untouched, there are at least three ways a reboot can work. In 1985, Robert Zemeckis and Bob Gale struck gold with the first Back to the Future movie. Its precise blend of sci-fi elements and lighthearted spirit, coupled with the pitch-perfect casting of Michael J. Fox as Marty McFly and Christopher Lloyd as Doc Brown, quickly made Back to the Future a massive hit, leading to two back-to-back sequels that completed a self-contained trilogy.
Michael J. Fox and Christopher Lloyd's legacy make it very hard for a fourth Back to the Future to match the original trilogy's popularity, even if a remake finds a talented cast and a creative director. But taking into account the Hollywood industry's penchant for remakes and reboots, it wouldn't be out of the ordinary to see a Back to the Future reimagining in the works in the near future. In that case, a new Back to the Future movie could aim to capture the original trilogy's charm but still respect its legacy by exploring a new era, possibly with new characters, new time-traveling shenanigans, and a brand-new story that doesn't just rehash the first three movies — giving it a variety of ways to execute a solid continuation to the franchise.
Back To The Future 4 Can Use The Multiverse Theory
Back to the Future is all about time-travel. But as many famous multiversal stories can attest to, time-travel tends to bring multiversal consequences with it. Marty McFly ensured his own birth when he helped his parents meet in 1955, but he also changed certain details that transported him to Back to the Future's slightly different 1985. In this new timeline, Lorraine and George McFly were wealthy and Biff Tannen worked as their valet. A similar thing happened when the older Biff Tannen stole the sports almanac from 2015 and gave it to his younger self, thus creating a dystopian timeline where Biff reigned over Hill Valley. Given how easy it is to create new timelines, it's possible that someone out there caught a glimpse of one time-traveling "variant" of Marty, Biff, or Doc Brown and got the idea to exploit time travel for their own benefit, just like Biff Tannen did in Back to the Future Part II.
It seems like each Back to the Future timeline gets overwritten every time someone travels through time. However, a Back to the Future reboot could reveal that each new timeline continues to exist parallel to the main one. Marty McFly and Doc Brown made sure no time paradoxes damaged the flow of time, but that doesn't mean a loose end can't come back to threaten the timeline. After all, Doc Brown drove off with Clara Clayton and his sons in his time-traveling locomotive at the end of Back to the Future Part III, presumably to travel across the ages, further diverting the timeline into multiple branches where many alternate-universe stories can take place. One of those alternate universes could even house a Marty McFly and a Doc Brown who look slightly different than their original selves, both on their own quest to fix the past or protect the original Marty McFly while he tries to get their parents to meet, just like he did in Back to the Future Part II.
Back To The Future 4 Can Copy Ghostbusters: Afterlife
Equal parts remake, sequel, and reboot, Ghostbusters: Afterlife found the recipe to honor the original Ghostbusters' legacy and establish a potential fresh start for the franchise. Likewise, a new Back to the Future movie could mirror the events of the first movie in order to capitalize on nostalgia, but also include actors from the original trilogy to keep the new story within the same universe and establish a clear new starting point with a different cast. It's a complex formula to balance, but it aims to appease every kind of feeling audiences may have towards the idea of a new movie not starring Michael J. Fox and Christopher Lloyd.
Of course, like Ghostbusters: Afterlife's addition of the original Ghostbusters during the movie's climax, a Back to the Future series reboot could find a place for Michael J. Fox and Christopher Lloyd to cameo, so they can join the adventure and give the new cast a hand. This progressive transition has become a popular passing of the torch for famous franchises like Star Wars, Rocky, Terminator, and the Marvel Cinematic Universe, though a simple appearance by the original cast isn't always guaranteed to help it succeed. That's why any new story needs to be able to stand on its own in the first place.
Back To The Future 4 Can Be A Brand New Story
The boldest option for a new Back to the Future movie is to start fresh. With only Back to the Future's concept of time travel, a brand-new cast can build their own time machine — possibly in the form of a fridge, like Back to the Future's original concept of the time machine before the DeLorean — and go on their own adventures in Back to the Future’s universe. It could be a spiritual sequel with no narrative connection to any event or character from the original movies, or it could justify a new trip through time by having the new characters directly address Marty McFly's and Doc Brown's adventures, similar to the vague but direct connection Jumanji: Welcome to the Jungle and its sequels have to the original movie.
Perhaps Doc Brown left his research in the Old West, or Marty McFly himself decided to reveal his time-traveling adventures to his children and grandchildren. Either way, this direct sequel could also deliver on what Michael J. Fox would like to see in a Back to the Future remake: a female Marty McFly. The creation of a brand-new story that doesn't attempt to rehash the original trilogy could avoid the constant comparisons that other gender-swapped reimaginings like 2016's Ghostbusters or Ocean's 8 have had to endure. Originality is the name of the game when it comes to a followup to such a beloved and popular franchise, and bringing a bright and lively new cast to the series might be just what it needs to continue onwards.