Marty shook his head. He couldn’t understand a word.
‘English, Doc,’ he requested.
Doc picked up a fallen blackboard and propped it up against the table. Another moment’s search, and he had located a piece of chalk.
Doc drew a straight line on the blackboard.
‘Imagine that this line represents time. Here’s the present, 1985 -’
He wrote ‘1985’ in the centre of the line.
‘The past -’
He wrote ‘PAST’ to the left.
‘And the future.’
To the right of ‘1985’, he scrawled a big, fat ‘F’.
‘Now, prior to this point in time’- he pointed again to 1985 -‘somewhere in the past’- he put an ‘X’ above the line in the past -‘the time line was skewed’- he drew another line, from the middle of the past, straight down toward the bottom of the blackboard - ‘resulting in this alternate 1985. Alternate to you, me and Einstein, but reality for everyone else.’
Marty shook his head. ‘I still don’t get it, Doc.’
Doc reached in the pocket of his lab coat, and pulled out a silver bag.
‘Recognise this?’ he asked. He handed the bag to Marty. ‘It’s the bag the Sports Book came in. I know, because the receipt was still inside.’ Doc passed the receipt over, too. Yep, there it was, the name of the Antique Store, followed by the words ‘PURCHASED: GREY’S SPORTS ALMANAC 1950-2000’ and the incredibly inflated price. It was the book Marty had bought, and here was the bag he had carried it in. But Doc had thrown the book and the bag away, hadn’t he?
‘I found them in the time machine,’ Doc continued ‘along with this -’.
Doc pulled out a brass ornament on Ae top of a broken pole. Marty had seen that ornament before It was in the shape of a fist. In fact, he had personaUy felt that ornament, when a certain older gentleman had knocked him with it and called Marty a ‘butthead’ - in 2015! So Marty wasn’t at all surprised when he read the name engraved on the palm:
‘Biff H. Tannen’
This was the top of Biff’s cane,’ Marty explained, although he guessed that Doc already knew it. ‘Old Biff, in the future. And you found it in the DeLorean?’
‘Correct!’ Doc raised a finger to drive home his point. ‘It was in the time machine because Biff was in the time machine, with the Sports Almanac!’
‘Holy shit!’ Marty replied.
‘You see,’ Doc continued, obviously proud of his deductive abilities, ‘while we were in the future’- he pointed at the big ‘F* on the blackboard -‘Biff got the sports book, stole the time machine, went back in time and gave the book to himself at some point here - he drew a long arc, all the way from the ‘F’ to the ‘X - in the past!’
He picked up another of those large newspaper volumes from the floor, and opened the book at the place he had marked with a piece of broken ceiling tile.
‘Look.’
The headline on this issue read:
HV MAN WINS BIG AT RACES!
Underneath that was a photo of Biff collecting his winnings at the pay window.
Doc slapped the paper in front of Marty.
‘It says right here that Biff made his first million betting on a horse race in 1958. He wasn’t just lucky.
He knew - because he had all the race results in the Sports Almanac!’ Doc’s point making finger rose one more time. ‘That’s how he made his entire fortune!’
He pulled one more thing out of his lab coat pocket.