On October 26, 1985, Marty McFly receives a call from his friend, Dr. “Doc” Emmett Brown, a scientist and inventor, instructing Marty to meet him at the Twin Pines Mall that night at 1:15am. At Hill Valley High School, Marty auditions for a Battle of the Bands, but is rejected after the judges deem his music too loud. Marty’s girlfriend, Jennifer Parker, gives him a pep talk after school, but they are interrupted by an older woman handing out pamphlets to protest the replacement of the town’s broken clock tower; the tower, which was struck by lightning in 1955, has become a landmark, but the mayor has plans to replace it with a working clock. At home, Marty finds his father George in the living room with his boss, Biff Tannen, who has just wrecked George’s car. Unapologetic, Biff commands George to work overnight. At dinner, Marty’s mother Lorraine expresses her disapproval of Marty’s girlfriend after hearing that Jennifer left two phone messages for Marty. Marty’s older sister, Linda, asks how she will ever meet a boy under Lorraine’s strict rules of decorum, and Lorraine promises that it will “just happen,” recalling how she met George as a teenager after her father, Sam Baines, ran him over with a car. Lorraine describes the night she took George to the “Enchantment Under the Sea” dance and the moment they first kissed on the dance floor. That night, Marty meets Doc at the Twin Pines Mall and films him with a video camera as Doc presents the greatest experiment of his life, a car that has been rigged to travel through time. To demonstrate the car’s capabilities, Doc straps his dog, Einstein, into the driver’s seat and uses a remote control to start the car’s engine; as the vehicle speeds across the parking lot and reaches eighty-eight miles per hour, it disappears, leaving two trails of fire in its wake. Soon after, the car reappears, covered in ice, with Einstein safe inside. Doc checks a watch around Einstein’s neck and confirms that it is now one minute behind as he sent the dog one minute into the future, but due to the nature of the machine, the dog arrived at the destination instantaneously. Doc shows Marty how to set a “destination time,” using the date November 5, 1955 as an example and explaining that it was the day he invented the “flux capacitor,” a device inside the car that makes time travel possible. Doc confesses to stealing plutonium from a group of Libyan nationalists, since the machine requires plutonium for fuel. Marty continues filming as Doc prepares for his first voyage, but the Libyan nationalists appear and shoot Doc, killing him. Fleeing the Libyans, Marty steals into the time machine, and when he reaches eighty-eight miles per hour, he travels back to the last destination time set: November 5, 1955. Upon arrival, the time machine runs out of fuel, and Marty hides it behind a billboard. Walking into town, Marty marvels at 1950s automobiles and storefronts. At a diner, Marty orders a drink, and Biff, now a teenager, barges in, yelling for “McFly.” Marty responds, but realizes Biff is talking to his father, George, the teenager sitting beside him at the counter. When Biff becomes aggressive with George, Marty stares, stunned to see his father as a young man. Marty follows George outside the diner and, later, sees him perched in a tree, peeping through binoculars at a teenaged Lorraine. George falls from the tree and is nearly hit by a car, but Marty pushes him out of the way and gets hit instead. The driver, Lorraine’s father, Sam, rescues Marty and takes him inside. That night, Marty wakes up to find young Lorraine tending to him. Marty joins the Baines family for dinner and meets his grandmother, Stella, along with his aunt and uncles, who are now children. When Stella asks if she can call Marty’s parents, he lies that they are out of town, and Lorraine flirtatiously squeezes his leg under the table. Disturbed, Marty leaves, rushing to Doc’s house. There, Marty informs a younger Doc that he has traveled to 1955 in a machine built by Doc thirty years in the future. To prove his story, Marty leads Doc to the vehicle and shows him the flux capacitor, the same device that young Doc conceived and sketched earlier that day. When Doc learns that plutonium is required to run the vehicle, he tells Marty they won’t be able to restart the machine, saying that the only comparable power source would be a bolt of lightning. At that, Marty produces the pamphlet he was given back in 1985 describing the effort to preserve the town’s clock tower. The pamphlet states that the tower was struck at 10:04pm the following Saturday in 1955, and Doc and Marty make plans to harness the lightning for fuel. Doc asks if Marty has interacted with anyone else in 1955, and Marty admits that he has met both his parents. Requesting to see a family photograph from Marty’s wallet, Doc discovers that Marty’s brother, Dave, has almost disappeared, suggesting that Marty’s interference has changed the course of his family history. Convinced that Marty ruined Lorraine’s chances of meeting George when he saved him from being hit by Sam’s car, Doc orders Marty to stay by George’s side to ensure that he takes Lorraine to the “Enchantment Under the Sea” dance the next night. At the school cafeteria, George tells Marty about the science fiction stories he writes, and, later, Marty sneaks into George’s bedroom dressed as an extraterrestrial named “Darth Vader.” Threatening to melt George’s brain, Marty convinces him to ask Lorraine on a date. The next day, Biff bullies George when he tries to talk to Lorraine at the diner, and Marty punches Biff, inadvertently drawing attention to himself. Outside the diner, Marty uses a makeshift skateboard to escape Biff’s gang, and after sending Biff’s car into a manure truck, Marty further impresses Lorraine. At his home, Doc presents Marty with a plan to fuel the time machine by running a cable from the clock tower to the street. The time machine will be rigged with a pole to make contact with the cable, jolting the vehicle with enough power from the lightning bolt to travel back to 1985. Lorraine arrives at Doc’s house and asks Marty to the dance. Although Marty suggests she go with George, Lorraine says she wants a strong man like Marty. Later, Marty strategizes with George, saying he will make take advantage of Lorraine before the dance so that George can step in and save her. On the night of the dance, Marty writes a letter to Doc alerting him that he will be shot on the night of October 26, 1985. He slips the letter into Doc’s coat and, later, drives Lorraine to the dance. Parked outside the high school, Lorraine kisses Marty, but stops herself when she has a strange feeling. Biff opens the door and pulls Marty out of the car, handing him over to his gang. Biff then moves inside the car, forcing himself onto Lorraine. George arrives, thinking he’s interrupting Marty and Lorraine, but finds Biff instead. Lorraine begs for George’s help, and though Biff easily overpowers him, George becomes irate and retaliates, knocking Biff to the ground. As Lorraine takes George’s hand, Marty follows them inside to make sure they kiss on the dance floor, sealing their fate as his future parents; however, the band has stopped playing after losing a guitar player, so Marty picks up the guitar to keep the dance going. Checking his family photo, Marty sees that his brother and sister have both vanished, and his face is disappearing. Marty loses the ability to play guitar, but when George kisses Lorraine, Marty revives. Just before 10:04pm, Marty meets Doc in town and Doc sets Marty’s destination time to the minute he left 1985. Doc finds the letter Marty left and becomes angry, ripping it up and saying he doesn’t want to know what happens in the future; meanwhile, a cable breaks and Doc must fix it at the top of the tower. With the pole affixed to the time machine, Marty sets his destination time to ten minutes before he left 1985, hoping to save Doc from the Libyans. Doc reconnects the cable, the time machine gets powered by the lightning and Marty successfully drives into the future. When he arrives back in 1985, Marty witnesses Doc being shot by the Libyans as the previous version of Marty escapes in the time machine. Surprisingly still alive, though, Doc shows Marty his bulletproof vest and presents the reconstructed letter that Marty wrote him in 1955, proving that Marty’s warning saved his life. Doc says goodbye to Marty before traveling thirty years into the future. In the morning, Marty discovers that his home is better furnished and that his brother and sister are more successful than when he last saw them; moreover, Lorraine and George are surprisingly well-dressed and flirtatious. Outside, Biff waxes George’s luxury car as copies of George’s first science fiction novel arrive in the mail. Jennifer arrives and greets Marty with a kiss, but they are interrupted when Doc returns in the time machine. Doc insists that Marty and Jennifer join him, as their future children are in danger, and the three take off in the time machine, heading back to the future.