Doc Brown's Entire Back To The Future Timeline Explained

Marty McFly (Michael J. Fox) may be the main character of the Back to the Future trilogy, but Emmett "Doc" Brown (Christopher Lloyd) manages to have quite an adventure as well — one which starts before Marty's and keeps going long after Marty's is complete. In fact, none of Marty's romps through time would've ever come to pass if not for Doc's scientific curiosity, his drive to innovate, and of course, his fascination with time travel.

Although Doc Brown is never the central focus of Back to the Future, his actions often drive the story, and his journey as he bounces around in time runs the full gamut of human experience, from falling in love and having children to dying (twice) ... although not necessarily in that order. While Doc's timeline does overlap with Marty's quite a bit, they're not entirely the same, and tracing Doc's trajectory through the movies leads to some interesting places, splitting into seven separate timelines. To make sense of them, we'll start when Doc first invented time travel, and then follow him as he begins to jump back and forth through time.

There would be no Back to the Future trilogy without the invention of time travel, and there would be no invention of time travel without — appropriately enough — a clock. On November 5, 1955, Doc Brown decided to hang a clock over the toilet in his bathroom, and the rest was history (and the future ... and alternate history ... and alternate futures). While balancing on his toilet, Doc fell and hit his head, knocking him unconscious. When he came to, he'd had a vision of the flux capacitor, the device that makes time travel possible.

We don't know how long Doc spent translating his vision into reality, but sometime over the following 30 years, he was successful in creating a working flux capacitor, which he then set about installing in a DeLorean. Meanwhile, on November 12, a week after falling off his toilet, while Doc was likely still trying to make sense of his bathroom epiphany, the clock tower at the Hill Valley courthouse was struck by lightning. At the time, this event didn't seem related to Doc's tumble off his toilet, but eventually, they'd wind up inextricably linked.

Three decades after inventing the flux capacitor, Doc finishes his time machine, but there's just one small hitch in testing it out. In order to run, his machine requires 1.21 gigawatts (perplexingly pronounced "jiga-watt" in the film) of power, which is significantly more than your average car battery can produce. Doc's solution? Just juice up the car with a little plutonium.

Of course, as Marty points out, plutonium is hardly something you can just buy at the store, but Doc has an answer for that, too. In a totally foolproof plan, Doc makes a deal with a group of Libyan terrorists to build them a bomb, steals their plutonium, and gives them a bomb casing filled with used pinball machine parts. What can possibly go wrong?

Turns out, quite a bit. In October 1985, Doc asks Marty to come help him document the first test of his time machine in the parking lot of the Twin Pines Mall, but no sooner has he conducted a successful test with his dog, Einstein, than the Libyans show up, incensed that Doc has stolen their plutonium. Marty hides, but Doc knows he's been found and braces for his fate. Sure enough, the terrorists open fire and kill Doc as a traumatized Marty looks on. Marty then tries to escape in the DeLorean, still programmed by Doc for the day he first invented time travel, bringing him back to November 5, 1955.

Not long after receiving his vision of the flux capacitor and bandaging the bump on his head, Doc Brown has just decided to test out his latest mind-reading invention when there's a knock on his door. When he opens it, a kid named Marty is standing there, claiming to be from the future and asking for Doc's help returning to 1985. At first, Doc doesn't believe him, but not only does Marty know how Doc got the bump on his head, but he's carrying a videotape that shows a much older version of Doc himself, purportedly testing out a time machine.

Convinced, Doc decides to help Marty hatch a plan to get him back to the future. Doc is initially stumped by the power requirements of the time machine, saying the only thing capable of producing the necessary 1.21 gigawatts is a bolt of lightning, but Marty then informs him that he does, in fact, know exactly when and where lightning will strike — the Hill Valley courthouse clock tower, on the evening of November 12, 1955.

Over the course of the next week (November 6-12, 1955), Doc spends much of his time making models of the town and fine-tuning his plan to harness a bolt of lightning into the flux capacitor. Due to the tight deadline and much to his chagrin, Doc doesn't have time to paint his model or make it fully to scale, but somehow, he muddles through.

While Doc is trying to make sure all the pieces are in place to get Marty back to the future, a wrench is thrown into his carefully laid plans when he realizes that Marty has accidentally bungled the timeline, preventing his parents from ever falling in love. Horrified at the temporal implications of what Marty has done, Doc assists Marty in making sure his parents get together before Marty is erased from existence.

After successfully matchmaking Marty's parents, Doc and Marty prepare to channel the imminent lightning strike into the DeLorean, but before Marty climbs into the car, he tries to give Doc a letter predicting his future. Furious about the possible effects that knowing his own future could have on the space-time continuum, Doc refuses to read the letter and rips it up. Marty is clearly upset, but he doesn't have time to argue. Lightning strikes, Doc's plan is successful, and Marty disappears in the DeLorean.

We don't know how long Doc carries around the ripped-up pieces of Marty's letter, but eventually, he decides to tape the torn scraps of paper back together and reads what Marty wrote. When he does, he learns that on the night Marty travels back to the future, Doc will be shot and killed by terrorists. In the letter, Marty urges Doc to "take whatever precautions are necessary to prevent this terrible disaster."

Doc takes Marty's advice to heart (although it doesn't stop him from stealing from terrorists in the first place). This time, when Doc goes to the mall to test his time machine, he wears a bulletproof vest underneath his coveralls and survives the shooting. When Marty asks him what made him change his mind about the disastrous implications for the space-time continuum, Doc gives him an extremely scientific explanation: "I decided, what the hell."

Having survived his formerly fatal encounter with the terrorists, Doc decides his next trip in the time machine should be to the future. On October 26, 1985, accompanied by his dog, Einstein, Doc sets out for the year 2015.

When Doc first arrives in 2015, everything about the future seems great. Cars are flying, clothing is self-adjusting, and movie theaters project holograms out into the street. Doc takes full advantage of the advanced technology of the future, placing Einstein in a suspended animation kennel while he modifies the Delorean with a hover conversion and adds a Mr. Fusion Home Energy Reactor to circumvent the need for plutonium. He also goes shopping for new clothes, picks up a sleep-inducing alpha rhythm generator, and visits a rejuvenation clinic to receive an "all-natural overhaul," which promises to add 30 to 40 years to his life.

However, while Doc is enjoying all of the amenities the future has to offer, he learns some troubling information about Marty's kids. It turns out that Marty's son, Marty Jr., falls in with Biff's (Thomas F. Wilson) grandson, Griff, and his gang, and he's with them when they rob the Hill Valley Payroll Substation. Marty Jr. is arrested and sentenced to 15 years in prison. Even worse, Marty's sister, Marlene, then tries to break him out of prison, and is subsequently sentenced to 20 years for her troubles. Unable to abide this future for Marty's family, Doc returns to 1985 to get Marty and change the future.

Having successfully picked up Marty and his girlfriend, Jennifer (Elisabeth Shue), from 1985, Doc pilots the now-flying DeLorean back to the future to prevent the bad choices of Marty and Jennifer's kids. Once they arrive, Jennifer quickly becomes excited with all the possibilities that time travel presents, such as getting to see her wedding, and Doc immediately knocks her out with his sleep-inducing alpha rhythm generator, saying she was asking too many questions. After stowing a sleeping Jennifer in an alley amidst packages of silicon and laserdiscs, Doc gives Marty a crash course on 2015 (kids wear their pants inside out!), then sends him forward with instructions to keep his son from getting arrested.

While Marty heads to the Cafe '80s to meet up with Griff, Doc intercepts Marty Jr. and uses the same sleep-inducing device on him to keep him from interfering in Doc's plan. Doc then goes to pick up Einstein from the suspended animation kennel. After meeting back up with Marty, Doc learns that he's purchased a sports almanac that covers the years 1950-2000. Doc berates Marty for even thinking about meddling with the timeline, and he forces him to throw the almanac away. Doc and Marty then pick up Jennifer and return to 1985.

When Doc and Marty return to 1985 from 2015, the timeline has already split thanks to Old Biff's tinkering in the past, which means that although the 1985 that Doc and Marty left had only one Doc Brown, the one they return to has two. Unfortunately, the Emmett Brown native to Timeline D has been declared legally insane and committed to the mental ward of Hill Valley Hospital by 1985.

Quickly, the Doc Brown from Timeline B, who's just arrived back from 2015, realizes that something must've happened to alter the timeline in the past, and he heads to the library to do research. Through studying old newspapers, he learns of the unfortunate fate of his Timeline D counterpart and deduces what's caused the divergence in the timeline — the sports almanac Marty purchased in 2015, which he spots in an old photo of Young Biff. As it turns out, when Marty tossed it aside in 2015, Old Biff grabbed it, stole the DeLorean, traveled to 1955, and gave it to his younger self, ensuring a future where he could become insanely wealthy.

Doc explains the concept of diverging timelines to Marty, who decides to head to Biff's massive casino hotel to confront the bully. While Marty is talking to Biff, Doc pilots the DeLorean to hover just below the roofline of the towering building, which is fortunate, since Biff forces Marty up to the roof, where he intends to kill him. Marty jumps on top of the DeLorean, and Doc uses the car's gull-wing doors to knock Biff unconscious. Armed with the correct date — once again, November 5, 1955 — Marty and Doc head back 30 years to restore the timeline.

Back in 1955 once more, Doc and Marty work together to steal the sports almanac from Biff in order to restore the timeline. While there, they also have to work to avoid their Timeline A and B counterparts, who are still living through the events of 1955 Timeline B. Doc is sure that if they encounter themselves in the past, it could have disastrous implications on the space-time continuum.

After a few failed attempts, Marty is ultimately successful in retrieving the sports almanac from Biff, grabbing it from the bully's car while riding on a hoverboard after a medium-speed chase. Marty narrowly avoids a potentially fatal crash when Doc drops a rope down to him from the flying DeLorean and pulls him to safety. Doc then tells Marty to burn the almanac, which he does, and they confirm that the timeline is restored.

However, before Doc can land the DeLorean and pick up Marty to return to 1985, the car is struck by lightning, causing the time circuits to go haywire and transport him to 1885. Back in 1955, the Timeline E version of Doc helps Marty figure out how to repair the DeLorean so that Marty can go after him. This version of Doc also dresses Marty in a truly unfortunate "cowboy" outfit, so that he'll fit in when he travels back to the Wild West.

After realizing what's happened and that the DeLorean has been so damaged by the lightning strike that there's no hope of repairing it enough to return to the future, Doc resigns himself to remaining in 1885. First, he hides the DeLorean in a cave, and he leaves a letter with the Western Union for Marty, telling him how to fix the time machine so he can return to the future. Doc gives the Postal Service extremely specific instructions to hold the letter for 70 years, then to deliver it to the person they'll find at a precise location at a precise date and time.

Satisfied that Marty will be okay, Doc begins building a life for himself. He becomes a blacksmith, using his futuristic scientific know-how to invent things like a mechanical refrigerator and ice maker. After establishing himself in town, Doc is asked to pick up the new schoolteacher, Clara Clayton (Mary Steenburgen), from the train station, and the two quickly fall in love.

Tragically though, not long after meeting Clara, Doc shoes a horse for Buford "Mad Dog" Tannen, which later throws Tannen off, causing him to break a $5 bottle of whiskey. Tannen shoots the horse, which he values at $75, and demands Doc pay for both. Doc refuses, and in retaliation, Mad Dog shoots him in the back, killing him.

After leaving the DeLorean for Marty and becoming a blacksmith but before meeting Clara, Doc rescues Marty from Mad Dog and his gang. (They were going to hang him, partially because of the outfit that 1955 Timeline E Doc picked out for him.) Initially, Doc is irritated that Marty traveled back for him, rather than returning to 1985 as he instructed, but after learning about his death in Timeline F, he agrees to return with Marty.

However, returning to 1985 proves easier said than done, since Marty nicked a fuel line in the time machine when he arrived in 1885, and there aren't exactly an abundance of gas stations in the Wild West. Without a way to self-propel the car, Doc hatches a plan to hijack a train and use the engine to push the DeLorean up to the necessary 88 miles per hour. However, after Clara and Doc meet and fall in love, she attempts to follow Doc onto the speeding train and winds up nearly taking a catastrophic tumble onto the tracks.

Instead of joining Marty in the DeLorean, Doc makes a split-second decision to save Clara instead, missing his window to return to the future. Marty goes back to the future alone, and Doc remains in 1885 with Clara. Fortunately, before stealing the train, Doc and Marty foiled Mad Dog's plans to kill Doc, enabling Doc and Clara to live their lives free of tragedy.

Some time after Marty departs for the future — and destroys the train by running it into a ravine — Doc and Clara get married and have two sons, Jules and Verne. During this time, seemingly inspired by his successful attempt to use a train to help facilitate Marty's time travel, Doc acquires a new locomotive engine, converts it to steam power, and modifies it to become a time machine.

Doc, Clara, and their children ride their new time machine all through the timeline, including a trip to the future where they update the train engine with hover technology and presumably a few other upgrades as well. When Jules and Verne are a few years old, Doc and Clara decide to make a stop in 1985 to pick up Einstein and to introduce Marty to their children. Doc gives Marty a framed photograph that they took together with the Hill Valley courthouse clock back in 1885, then he departs on his train for places and times unknown.