Just then, the doors fly open and in walks Biff and his friends Match, Skinhead and 3D, who have come to harass George. It turns out that Biff has been forcing George to do his homework, something George has been slacking off on. When George admits that he hasn't completed Biff's homework, figuring that it is not due until Monday, Biff gets annoyed, and raps George on the head, reminding George that he will get expelled if he hands in his homework in George's handwriting.
George finally agrees to finish up Biff's work and hand it over the next day. After Biff and his friends leave, the diner's busboy, Goldie Wilson (Donald Fullilove), chides George for letting Biff harass him all day. George insists that Biff is bigger than him, while Goldie points out that he doesn't expect to spend the rest of his own life working as a busboy.
He plans on becoming someone famous one day. Marty immediately recognizes Goldie and before realizing it, blurts out to Goldie that he's going to be mayor in 1985. This plants the idea in Goldie's mind and he begins to think about how as mayor of Hill Valley, and how he will clean up the town (to which Lou responds by giving him a broom and telling him to start sweeping the floor).
After George leaves the diner, Marty's curiosity is piqued and he follows him into another neighborhood. He momentarily loses track until he finds George's bike parked beneath a tree. He looks up and notices George on a tree branch, using a pair of binoculars to spy on a girl getting undressed in her room across the street. Marty is shocked to find that George is a peeping tom. George strains to get a better look.
George suddenly slips and falls out of the tree, landing in the street in front of an oncoming Cadillac. Marty instinctively rushes out and pushes George out of harm's way. The car slams on its brakes, but it hits Marty, who hits his head on the pavement and is knocked unconscious. George gets on his bike and rides away as Sam Baines, the driver, yells to his wife that another kid has jumped in front of his car.
When Marty comes around, it's night time and it is raining outside, and he is lying in an unfamiliar bed. His mother's voice tells him that he's been out for nine hours. Marty, still semi-conscious, quips about having a dream that he went back in time. Lorraine's voice reassures him that he's safe and sound in 1955. This prompts Marty to bolt upright just as a lamp is turned on, and he is promptly dumbstruck to see that in 1955, Lorraine is a rather attractive teenage girl.
Lorraine begins to hit on Marty almost immediately, thinking his name is "Calvin Klein" (due to that being the brand of underwear Marty is wearing). Marty instinctively panics when Lorraine tries to make advances on him and looks like she is trying to kiss him. Fortunately for Marty, this is interrupted when Lorraine's mother Stella calls her down for dinner.
At dinner, Marty meets the rest of Lorraine's siblings, including her brothers Milton and Toby, her sister Sally, and in the crib nearby, little baby Joey. Stella admits that Joey loves his crib, and cries every time they try to take him out. Marty recognizes Joey as the future prison inmate, and can't resist the urge to joke to the baby to "Better get used to these bars, kid..." The family eats while watching an episode "The Honeymooners" on the new television set that Sam has just brought home.
Marty immediately recognizes the episode they are watching as one he has watched in 1985, which he explains by saying that he saw it in a rerun. Marty asks how to find Doc's address, which Lorraine's father says is over on the east end of town. Marty knows that area as "John F. Kennedy Drive", a name that Lorraine's father doesn't know. As Marty leaves the house, Sam warns Lorraine that if she ever has a kid like Marty, he will disown her.
Marty makes his way over to Doc's house (which will be destroyed in a fire sometime in the next 30 years, which is why Doc lives out of his garage in 1985). When Doc, who does not recognize Marty, answers the door, we see that he has a bandage on his forehead from where he hit his head trying to hang a clock above his toilet. Without saying a word, he immediately hooks Marty up to his newest invention - a thought reader.
Doc determines that Marty comes from a great distance, and wants him to make a donation to the Coast Guard Youth Auxiliary. Frustrated, Marty tells Doc directly that his time machine works and he is from the future. Doc is skeptical, even when Marty shows him his future driver's license and a family photo. Doc comments that the photo must have been forged as Dave's hair is missing from the picture. However, Marty is able to convince Doc of the truth by mentioning the wound on his head that prompted the vision of the flux capacitor.