Doc stares at Darleen in utter amazement for a moment, "My God, do you know what this means?" He pauses dramatically as he removes the contraption from his head. Darleen shakes her head—waiting for him to continue. "That means that this damned thing doesn't work at all!" He throws the machine down, "Six months labor for nothing! Where did I go wrong?" Doc's brows knit together as he rubs a bandage on his head. Darleen sighs.

"Time machine? I haven't invented any time machine." Doc says to Marty causing the teen to pull out his wallet, "You will. Look, here's my driver's license. Expires 1987. See my birthdate? I haven't even been born yet!" He pulls out a picture, "Here's a picture of me, my sister, and my brother. Look at her sweatshirt—class of '84." Doc looks the items over. "Pretty mediocre photography fakery—they cut off your brothers head." Marty—not realizing that his brother's head is actually cut off—looks at Doc, but Darleen looks at the picture—a confused look on her face as Marty spoke.

"Please Doc! You've gotta believe me—us! We're telling the truth!" Doc narrows his eyes, "Then tell me, future boy, who's the president of the United States in 1985?" Marty answers quickly, "Ronald Reagan." Darleen reacts as she had before to Martys' obliviousness and face palms. "Ronald Reagan... the actor?" Marty nods resulting in Darleen face palming again. "And who's the vice president? Jerry Lewis? That's the most insane thing I've ever heard." Doc picks up the brain analyzer blueprints and rushes out the back door. Marty and Darleen walk after him.

——

Doc runs across the lawn—towards the garage—with the brain wave analyzer blueprints in hand. Marty chases after Doc as Darleen speed walks after the two—annoyed with both of them from the conversation they had before this. Doc's Packard is parked in the driveway. "I suppose Jane Wyman is the first lady—and Jack Benny is secretary of the treasury!" Doc runs up to the garage door and opens it. Marty comes up behind him as Darleen walks up behind Marty. "Please, Doc! Listen to us!" Doc turns around and faces the two teens.

"I've had enough of your practical jokes for one evening. Good night future boy and girl!" Doc slams the door in his face. He locks it. Darleen places a comforting hand on Marty's shoulder—he looks at her before getting an idea—he starts to yell at the door. "Dr. Brown! That bruise on your head! I know how you got it! It happened this morning! You fell off your toilet and hit your head on the sink! And then you came up with the idea of the Flux Capacitor—which is the heart of the time machine!" The two wait—the door unlocks. Doc opens the door—he looks at the two with new interest and rubs his bandaged head. "Doc, how could I—we, know that unless we were from the future?" Doc furrows his brows, "Take me to this—time machine."

——

Doc, Marty, and Darleen get out of Doc's Packard with flashlights. Darleen and Marty lead Doc to the hidden DeLorean. "There's something wrong with the starter, so we hid it back here." Darleen explains. The flashlights illuminate the abandoned DeLorean as they approach—Doc gasps in amazement as he looks at the vehicle—he pulls out a piece of paper from his pocket, "After I fell off my toilet, I drew this..." It's a sketch of the Flux Capacitor. Marty raises the gull wing and points at the real thing. Doc stares—his eyes light up and he starts jumping for joy. "Ha! It works! I finally invented something that works! Let's get this thing back to the laboratory—we've gotta get you two home."

——

The DeLorean is now in Doc's garage. Marty hooks up the video camera to a TV set while Doc examines the contents from the 1985 suitcase. "So these are my own personal belongings in here huh?" He pulls out a portable hair dryer. "What's this?" Darleen looks at him, "A hair dryer." Doc furrows his brows, "A hair dryer? Don't they still have towels in the future?" He pulls out his underwear, "And this underwear? It's all made of cotton, I thought for sure we'd all be wearing disposable paper garments by 1985." He pulls out a Playboy magazine—Darleen's eyes widen before sighing—not caring to stop the man.

He leafs through it and opens up the centerfold, "Hey...! Suddenly the futures looking a whole lot better!" Marty waves Doc over, "Okay, Doc—look at this." Doc drops the mag before walking over to where Marty is crouching by. Marty rolls the videotape he shot at the parking lot of the mall where Doc is explaining the operation of the time machine. Doc is amazed to see himself as an old man. "Why—that's me! Look at me! I'm an old man! Say—I don't look bad for an old geezer. Thank god I've still got my hair," he turns to the two teens, "baldness runs in my family you know. But—what on earth am I wearing?"

"A devo suit."— "A radiation suit." Both of the teens say at the same time in response. Doc nods, "Of course—because of all the fallout from the atomic wars. This is truly amazing—a portable television studio. No wonder your president has to be an actor—he's gotta look good on television." Marty—half-listening—points at the screen, "Watch this—this is the part coming up." The part of the plutonium—old Doc Brown stands next to a container of it. "Plutonium!? You mean this suckers nuclear!" Marty says in the video. "Electrical. But I need a nuclear reaction to generate the 1.21 gigawatts of electricity I need.."

Young Doc furrows his brows as his eyes widen, "What did I just say?" Marty rewinds it a bit before replaying it, "...I need a nuclear reaction to generate the 1.21 gigawatts of electricity I need..." Doc has a shocked expression on his face. "1.21 gigawatts? 1.21 gigawatts? Great Scott!" Doc runs like hell out of there—both of the teens are confused.

——

Doc runs out of the garage and back to the house. The teens look at each other before following him. Both of them make their way into the house through the back door. It sounds like Doc is talking to someone else in the other room. Both of them walk cautiously into the room. Doc is seated in a chair, "How could I have been so careless? 1.21 gigawatts. Tom! How am I gonna generate that kind of power? It can't be done—can it?" He's talking to a picture of Thomas Edison.