Work Text:
"Of course I can fix it," Doc said, flipping his headlamp back. "But what I'd like to know is, where - or, more to the point, when - did you get it?" He tapped the Oscillation Overthruster with a jeweler's screwdriver. "And why is it wired like that? There's no way a car battery can give it enough power."
"Rocket-fueled turbine with an iridium-oxide capacitor module attached to a hydrogen fuel cell." Buck pointed into the gear where the Jet Car's back seat would have been, had it had one. "Produces a juice-jolt of just under one and a - "
"One-point-twenty-one gigawatts, I know." Doc mispronounced "gigawatts," with a soft G; Buckaroo politely declined to point this out. "You didn't answer my question."
"I got it just outside of Princeton," Buckaroo said. "Why?"
Doc leaned back out of the Jet Car's window and flipped the headlamp back down, shining it in Buck's face. "Because I'm the only person who knows what a flux capacitor even looks like now, and I haven't built it yet. To have one, you have to have gotten it from a future version of me, or possibly from Marty when he got back to the future. And I have no way of knowing whether you begged it, borrowed it - or stole it." He scowled. "I don't relish the idea of helping out someone who may well be going to stick a gun in my face somewhere down the line."
"Of course," Buck sighed. "Whorfin must have thrown me off course the other way this time."
"Other way?" Doc looked confused for a moment.
Dr. Banzai put his hands flat on the hood of the Jet Car. "I realize this must sound strange, but I built the Jet Car - me and my team - and the Oscillation Overthruster is my work, based on my father's, Professor Hikita's, and Dr. Emilio Lizardo's."
"Lizardo," mused Doc. "Wait, isn't he the professor from Berkley who got himself shot chaining himself to the main gate of a nuclear reactor? Said every time we smashed an atom, we risked opening a gate to some Lovecraftian dimension?"
Buckaroo's eyes opened wide for a second. "Not in my world."
Doc blinked. "Your? - oh." He leaned back in through the window of the Jet Car, tracing the lines of the Overthruster with his fingers. "You're saying you're from a parallel world, where you beat me to this technology?"
"More or less," Banzai agreed.
Doc slid back out and stood up straight. "Same era?"
"It's 1987 where I'm from." Banzai looked around; Doc's workshop was littered with clocks and calendars. The closest one said it was May of 1979.
"Great Scott!" Doc pressed a hand to his chin. "I don't know why I believe you, but I think I do. I would never have wired the time circuits to a single switch like that."
Banzai smiled. "In my universe, it doesn't travel through time; it lets you travel through solid matter via dimensional displacement."
"Spacewise instead of timewise? Your chronospatial constant must be higher, then." Doc reached for a welding torch and a screwdriver. "Let's go ahead and take the door off so we can access it. You really should have put gull-wing doors on this monstrosity . . ."