Doc: Alternate to you, me and Einstein. But reality for everyone else.
Doc: Recognise this? It's the bag the sports book came in. I know, because the receipt is still inside. I found them in the time machine, along with this!
Marty: It's the top of Biff's cane, I mean old Biff from the future!
Doc: Correct! It was in the time machine because Biff was in the time machine - with the sports almanac!
Marty: Holy shit!
Doc: You see, whilst we were in the future, Biff got the sports book, stole the time machine, went back in time and gave the book to himself at some point in the past.
Doc: Look!
Marty: The almanac!
Marty: He must have been listening when I..... it's my fault! If I hadn't bought that damn book, none of this would ever have happened!
Doc: Well, that's all in the past.
Marty: You mean the future.
Doc: Whatever! It demonstrates precisely how time travel can be misused and why the time machine must be destroyed - after we straighten all of this out.
Marty: Right, so we go back to the future, and we stop Biff from stealing the almanac.
Doc: We can't! Because, if we travel into the future from this point in time, it will be the future of this reality!
Doc: No, our only chance to repair the present is in the past, at the point where the timeline skewed into this tangent. In order to put the universe back as we remember it, and get back to our reality, we have to find out the exact date, and the specific circumstances of how, where and when, young Biff got his hands on that sports almanac.
Marty: I'll ask him.
Biff: Bullet-proof vest! Great flick, great frigging flick The guy is brilliant!
Biff: Hey, what the hell's going...
Jacuzzi Girls: Ahh!
Marty: Party's over Biff.
Marty: Sorry ladies.
Biff: How'd you get past my security downstairs?
Marty: There's a little matter we need to talk about.
Biff: Yeah, money, right? Well forget it!
Marty: No, not money.
Biff: You heard him girls, party's over.
Biff: Start talking kid, what else do you know about that book?
Marty: First, you tell me how you got it. How, where, and when.
Biff: Alright, take a seat.
Biff: Sit down!
Marty: November 12th 1955? That was the day I went back...
Biff: You know your history, very good. I'll never forget that Saturday. I'd just picked my car up from the shop because I'd enrolled it in a drag race a few days earlier.
Marty: I thought you crashed it into a manure truck.
Biff: How do you know about that?
Marty:
Biff: Your father?
Marty: Before he died.
Biff: Yeah right. So there I was, minding my own business
Biff: He says he's my distant relative. I didn't see any resemblance.
Biff: So he says "How would you like to be rich?" So I say "Sure."
Biff: So he lays this book on me. He says this book'll tell me the outcome of every sporting event 'til the end of the century. All I have to do is bet on the winner, and I'll never lose. So I say "What's the catch?" He says, "No catch, just keep it a secret."
Biff: After that he disappeared. I never saw him again.
Biff: Oh, and he told me one other thing. He said some day, a crazy wild eyed scientist or a kid may show up asking about that book. And if that ever happened.....
Biff: Funny, I never thought it would be you.
Marty: Yeah well Biff, you're forgetting one thing. What the hell is that?
Biff: You're dead, you little son of a bitch!
3-D: Hey, get back here!