The DeLorean drifted away from Hill Valley Square, its hover engines buzzing against the afternoon sky. Marty sat in the passenger seat, staring at his trembling hands.
He had just saved his son from disaster... but he couldn't shake the unease creeping into his gut.
Jennifer was still pale, shaken by what she had seen in her future home.
And Doc, gripping the wheel with a grim set to his jaw, looked more concerned than ever.
Marty cleared his throat. "So that's it, right? My kid's safe, and we can just… go home?"
Doc shook his head. "If only it were that simple. The future isn't written in stone, Marty. Every action we take can ripple outward like waves on a pond. We've merely prevented one disaster... but countless others are always possible."
Marty slumped in his seat... Great. Saved the kid, but still screwed.
The DeLorean touched down on a quiet rooftop. Doc led them into a nearby alleyway where a row of automated shops and vendors glowed with digital lights.
He handed Marty some cash akin to futuristic bills that shimmered slightly. "Here, go blend in. Don't draw attention. Remember: no meddling. The last thing we want is for you to..."
But Doc didn't finish. His eyes darted nervously toward a newsstand.
Marty followed his gaze and froze. There, stacked on glossy display, was Grays Sports Almanac: 1950–2000.
The bold cover boasted complete scores and statistics for fifty years of football, baseball, horse racing... everything.
Marty's brain lit up like fireworks. Fifty years of guaranteed winners. Bets, races, scores... all known ahead of time. It was the ultimate jackpot.
He picked it up, thumbing through the pages. "Doc… do you realize what this is?"
Doc's face darkened instantly. "I certainly do, Marty. And that's exactly why you must put it back immediately."
"Come on, Doc! We could make a fortune with this. One bet on a World Series, a couple of horse races... we'd be set for life!"
"No!" Doc snapped, snatching the book from Marty's hands. "I didn't invent the time machine for gambling and personal gain! Using time travel for such trivial purposes could have catastrophic effects. Whole histories warped, entire lives destroyed, all because of greed."
Marty muttered under his breath, frustrated, but he couldn't push back against Doc's conviction.
The scientist stuffed the almanac into a trash can, sealing the matter... or so he thought.
Neither noticed the figure lurking nearby: Old Biff Tannen.
His wrinkled face was twisted with suspicion as he watched the exchange from the edge of the alley.
When Doc and Marty turned to leave, Biff shuffled toward the trash can and plucked out the discarded book. His hands trembled as he flipped through the pages. A smirk spread across his lips.
"This could be my ticket…" He muttered.
--------------
Meanwhile, Doc, Jennifer, and Marty returned to the DeLorean, preparing to leave 2015 behind.
Jennifer was still woozy, and Doc tucked her into the back seat. As he adjusted the circuits,
Marty noticed the almanac again. Doc had retrieved it from the trash, intending to dispose of it properly. He was explaining the dangers of temptation when he was interrupted by a buzzing noise.
A gang of robotic police officers appeared, like RoboCops scanning the alley.
They spotted Jennifer slumped in the back seat and immediately rushed over. "Hey, that looks like Jennifer Parker!"
One of them exclaimed. "Come on... let's get her home. She lives on Glen Oaks Drive."
Marty tried to protest, but the officers were too fast. Before Doc could react, Jennifer was carried into a hovering squad car and whisked away.
Doc paled. "This is bad. Very bad. If she meets her future self again..."
"Then let's go after her!" Marty shouted.
They soared after the police car, tailing it through the neon-splashed skyline until it descended into Jennifer's future neighborhood.
The officers carried her inside, placing her unconscious body on the porch of the McFly home.
Seconds later, she stirred awake.
Confused, Jennifer slipped inside and found herself face-to-face with her older counterpart once more.
The house was chaos: Marty Jr. lounged in front of a giant TV, while her daughter argued with him.
Then, future Marty himself appeared... aged, worn, limping from an old injury.
Jennifer hid in shock as she watched her future husband humiliated at work, berated by his boss and bullied into shady deals.
The weight of it all crushed her. Was this really her future?
Before the disaster could escalate further, Doc and Marty burst inside.
They grabbed Jennifer and rushed her back toward the DeLorean.
Alarms blared as future family members screamed in confusion, but Doc forced them through the door and sealed it shut. "We've tampered enough with this timeline. Time to leave!"
They didn't notice Old Biff following them.
As Doc fiddled with the circuits, Old Biff crept up to the parked DeLorean, slipped inside, and slammed the gull-wing door shut.
He'd seen enough to know how this machine worked. With the almanac clutched in his hands, he fired up the engine and launched into the sky.
Hours passed before the car returned, battered from its journey. Old Biff, groaning in pain, stumbled out and limped away.
The DeLorean sat quietly until Doc and Marty emerged from their hiding spot, unaware that anything had changed.
"All right." Doc sighed, exhausted. "We've meddled enough in the future. Time to go back to 1985 and put this all behind us."
The car soared into the timestream, flames licking at its wheels. But when it landed, something was wrong.
The Hill Valley they returned to wasn't the one they'd left. It was darker, dirtier, and corrupted. Police sirens wailed in the distance. The town square was filled with grime, neon sleaze, and chaos.
The courthouse had been transformed into a casino-hotel, its gaudy lights blazing "BIFF'S PLEASURE PARADISE."
Marty stumbled into the streets, aghast. "Doc… what the hell happened to Hill Valley?"
Doc's eyes widened with horror. "Someone's altered the timeline. Someone took the DeLorean back and tampered with the past."
The answer became clear when they confronted Biff.
Not the bumbling loser Marty knew... but now a wealthy, ruthless tyrant ruling the city with an iron fist.
He revealed, smugly, that he had received a mysterious book in 1955... a book filled with sports scores.
With that knowledge, he built an empire of gambling and corruption, twisting Hill Valley into a nightmare.
Marty's heart sank. The almanac. Old Biff. It all clicked together.
Doc's face went pale. "Great Scott! We're not in our timeline anymore. We've created an alternate 1985."
Marty clenched his fists. "So how do we fix it?"
"There's only one way," Doc said gravely. "We have to go back to 1955. Back to the day Old Biff gave your younger grandfather the almanac... and stop it from happening."
The DeLorean's engine roared once more. The sky split open in streaks of lightning as Marty and Doc vanished into the timestream, leaving behind the nightmare world Biff had created.
The future had given them one lesson: time travel was dangerous. But the past was waiting... and their fight wasn't over.