Marty walked down several streets while trying to locate Biff.  He had to be careful or else his parents or someone he might have met in his initial romps through 1955 might recognize him and tell everyone else.  He only had to hide twice before he met up with Jake.  They then walked down the main street where Marty had driven the DeLorean into the future.  The singed wire still hung above the street since no one had bothered to take it down.

"So this is the site of your return to the future, or my past," said Jake.  They walked down in the street in silence.  Marty opened his mouth to say something.

"Don't bother asking it.  I gave Sarah Temporal Psychosis.  She knows it and so do I.  She agreed to be used as a guinea pig in my experiment that would make her know who altered a timeline in any time period and seek that person out.  However she eliminates the link rather than bother fixing it and she can't stop that impulse thus it's Temporal Psychosis.  Right now she's probably purchased a rifle of sorts and is now tracking Biff at this very moment.  She'll eliminate him and as a result alter the timeline even more," said Jake.  They walked down the street in more silence.

"So where's Tannen?" asked Jake changing the subject.

"I lost track of him when Sarah decked me," said Marty.

"It's not your fault.  However we must find him and save him from Sarah," said Jake.  Marty laughed.

"Save Tannen.  I never thought I'd do that," said Marty.  Jake shrugged.

"It happens," he said.

A few blocks away: Biff was walking down the street completely unaware of the high- powered rifle aimed at him from the roof of a store nearby.  Sarah aimed the scope at his head and pressed the trigger.  Nothing happened.  Sarah checked the gun and realized the safety was still on.  By the time she clicked it off and aimed the rifle again, Biff was nowhere in sight.  Sarah scowled and slung the rifle behind her and walked off towards the stairs and down onto the ground level.  She hid the rifle in a box of roses and walked down the street with it like in a movie she'd seen that wouldn't come out for another thirty-seven years after this time period.

Street: Marty and Jake walked down another street.

"So Jake.  Any chance we'll meet a younger version of you?" asked Marty.

"No.  I was born yesterday in a town well away from here," said Jake.

"Wow.  That's the same day of the famed lightning storm.  Say Jake, do you know why yesterday was such an important date.  I mean the day I traveled into the future, Biff from the future arrived and gave the book to the younger Biff and I chased him.  Oh forget it, it doesn't make any sense," said Marty giving up.

"Yeah fourth dimension is some pretty crazy stuff.  I understand what you're asking and here's your answer," said Jake turning back and pointing at the courthouse and the wire going across the street.

"The lightning bolt that hit was a massive lightning bolt.  So massive that it stopped the clock.  The lightning bolt then proceeded into the flux capacitor and you were sent home.  However it was the lightning bolt's interaction with the capacitor that cemented that day in the fourth dimension.  Time cannot be significantly altered prior to November 12, 1955 10:04 p.m.  It isn't possible," said Jake as he turned around and walked down the street.

"Yeah but didn't Biff give the book to himself before that?" asked Marty.

"True.  But the events still played out the same.  Biff was still knocked out by your father and you father and your mother still got together.  After you journeyed into the future, Biff betted on the races and killed your father.  You returned and corrected that mistake.  Time right now can be altered although it's our duty to see that it doesn't," said Jake.

"Right," said Marty.  They walked down another street and saw Biff.

"C'mon.  If we tail him and then Sarah creates an incident, we can slip in, grab the book, and stop Sarah," said Jake.  They silently followed Biff down several more streets.  Biff eventually met up with his goons and they boarded their car and drove off.

"So much for that," said Marty.

"He'll show up again," said Jake.

"Yeah but where?" asked Marty.  A teenager walked up to them.

"Here you go.  Be sure to come to our dance now," said the teenager handing Marty a poster.  He looked at it.

"Looks like a dance in the other high school in Hill Valley," said Marty.

"This place has 2 schools?" asked Jake.

"Yeah but the other one was closed down years ago.  I think it was closed down in 58," said Marty.

"I suppose Biff might go to this," said Jake.

"We'd best get moving.  It's nearly dark and this dance is about to start and I don't think I can take Biff and his goons alone.  Do you want to come?" asked Marty.  Jake shrugged.

"Might as well.  I'm not positive I can find my way back to where the cars are," said Jake.  They got a ride to the high school and sat on some stairs overlooking the lot.

"I don't see Biff's car do you?" asked Jake.

"No.  But if Biff spots me, he'll be thoroughly pissed off at me.  I've wrecked his car twice and I don't think he wants it to happen a third time," said Marty.

"Good.  We can use you as bait should the situation arise," said Jake laughing.  Marty laughed also and it helped relieve some of the stress of their situation.

Billboard: Doc awoke and saw the note saying that Jake had gone into town.  Doc shrugged and started loading sticks and leaves into the flux capacitors of both the cars.  He had just finished when Sarah arrived.

"I doubt you stopped Biff yet, but what did Jake want to go into town for?" asked Doc.  Sarah shrugged.

"It was something important," she said.  Doc pulled out the radio.

"I'd better call him and ask," said Doc.

"I think he's under radio silence.  He'll call you when it's safe.  Same goes for Marty," said Sarah getting inside the Lamborghini.

"Oh.  Must be important then.  Where are you going?" asked Doc as Sarah started up the engine.

"Jake thought it would be better to move the Lamborghini to the other side of town so that way if he or Marty needed to be picked up at night, one car would be nearer thus limiting the amount of exposure to the people," said Sarah.  Doc nodded.

"Sounds reasonable.  Bye," said Doc.  Sarah gunned the engine and the Lamborghini took to the sky.  It then flew off over the city.  Doc then sat back inside the DeLorean and rummaged through the glove compartment.

High School: "There he is," said Marty.  The car pulled into the parking lot and Biff and his pals hopped out and entered into the high school.

"I think you'd better trail them," said Jake.

"Are you crazy?  I'd just get angry and a fight would ensue and I'd probably loose or do something stupid.  You're coming with me," said Marty.

"Nuts," said Jake.  They proceeded into the high school as a bright light soared overhead.  Inside they noticed Biff and his pals near the food.  Jake was about to proceed into the dance when Marty pulled him back.

"What?" Jake asked.

"That's Gerald Strickland.  If he busts us, we'll have a hard time explaining why I don't exist and why you are only a day old.  Let's just lay low," said Marty.  Jake looked out to see a bald man watching the dancers.

"That would not be good I agree.  I guess we should find a place to hold down the fort and watch them," said Jake.  They found a group of strategically located seats and sat down.  They waited for a few moments.

"If I know Sarah, she'll show up sooner or later.  I think we'd better deal with Biff and that book now.  Once the timeline is restored, she should return to normal.  If she shows up before we deal with Biff, I'll give her the counteragent," said Jake.

"But how do we lure him out of the gym?" asked Marty.

"Why don't I tell him that you're out here and then he'll come outside.  Between the two of us, he and his goons should be no match for our strength," said Jake.  Marty shook his head.

"Alright.  Of course you can't use my real name.  Use Calvin Klein," said Marty.  Jake's eyebrow shot up.

"Don't ask," said Marty.  Jake shrugged and walked off into the crowd while Marty went outside.  Marty saw Jake explain the situation to Biff who growled and started straight for the doors.  Marty walked out and waited on the steps.  Jake was about to proceed after them when he was stopped by Gerald Strickland.

"Who are you?" he asked.  Outside Marty stood face to face with Biff and his goons.

"What do you want kid?" asked Biff.

"I've returned for the second book," said Marty.

"You ain't getting it kid.  In fact, I'm ready to give you a bruising for ruining my car twice," said Biff.  Biff and his goons closed in on Marty as he tried to avoid their attacks while waiting for Jake to show up.

Inside: "I'll ask again, who are you?" asked Strickland.

"I'm a chaperone," said Jake.

"I don't think so.  All the chaperones here are parents and you're too old.  I'll have to report you," said Strickland.

"I can't let you do that," said Jake.  He slugged Strickland who fell to the ground unconscious.  Jake looked up to see everyone looking at him.  A moment later they started clapping and cheering, the chaperones included.  Jake nodded and hurried out of the building.  He arrived just as Marty hit the pavement.  Jake was about to help when he was hit in the stomach and fell also.

"Nice backup kid," said Biff preparing to drill Marty again.  Marty looked up at him weakly and noticed a red dot on his neck.  Marty used his last ounce of strength to tackle Biff as a bullet whizzed by their heads.

"What's this kid?  You got a hitman?  Screw you," said Biff.  He punched Marty and ran for his car as more bullets hit the pavement around him.  Then he jumped in his car and drove off.  Biffs henchmen ran as a black Lamborghini flew overhead and chased after Biff.  The two cars zipped around a corner and were gone.  Jake stumbled over to Marty.

"You okay kid?" asked Jake.

"Contact Doc.  We've got to chase them," said Marty weakly.

"Doc come in," said Jake.

"Hello Jake.  Done with your secret mission huh," said Doc.

"What're you talking about?  When did Sarah get the Lamborghini?" asked Jake.

"Awhile ago.  Sarah showed up and she said that you were on an undercover mission and you and Marty weren't to be bothered until you contacted me.  Then she hopped in the Lamborghini and took off," said Doc.

"I don't have time for specifics.  We're headed for Marty's high school.  Meet us on the roof.  There's too many people where we are to risk you coming to us," said Jake.

"Can you tell me what's up?" asked Doc.

"I'll tell you when you arrive.  Get moving.  We haven't much time," said Jake.  He and Marty took to the streets headed for the high school.

Billboard: Doc lifted the DeLorean above the billboard and was turning towards town when a truck stopped.  Farmer Peabody leapt out with his shotgun and aimed it at the DeLorean and fired.  The bullets wizzed by the car as Doc tried some evasive maneuvers.

"I'll get you space bastard!  And your friend!" exclaimed Peabody as he continued firing at the DeLorean as it streaked away from him.  Peabody growled in anger, leapt in his truck, and chased after it.

High school: "Where is he?" asked Jake.

"Doc will be here.  Be patient," said Marty.

"It's hard to be.  If Sarah kills Biff then the timeline will be restored and immediately collapse as a paradox is formed.  The whole universe will explode.  You ever hear of the Ghostbusters who are in New York?  The same thing would happen if they crossed the particle streams of their proton packs.  But much worse than that, what if the Lamborghini is damaged or destroyed!  Do you have any idea how much that thing costs?  Not only that, but you have to figure in the cost of the time travel equipment.  No!  Calm, must be calm," said Jake to himself.  Marty just shook his head.

"Look.  There's Doc," said Marty.  The DeLorean soared over the school and hovered a few feet above the parking lot.  Marty and Jake ran to the passenger side and got in.

"Tight squeeze," said Marty.  The two of them sat squished in the seat.

"This car wasn't designed for more than two people.  Go Doc," said Jake.  The DeLorean lifted up into the night sky and soared away.

"How do we find them?" asked Doc.

"Okay.  You see that dial that looks like a compass.  Follow the arrow.  It's designed to track any other time machine in this time period.  When the arrow's at the top of the circle you know you're going the right way," said Jake.  The DeLorean headed down the same road that it the previous DeLorean had traveled down earlier when Marty and Doc had chased Biff.

"Hold up.  This thing isn't going to detect the other DeLorean is it?" asked Doc.

"No.  I planted trackers in all of the time machines I built.  Even though I retrieved every part from the old DeLorean time machine and built the one we're in now with those pieces, there isn't one located in the DeLorean right now that you're referring to.  It is tracking the Lamborghini," said Jake.  The DeLorean flew on.

"Something just occurred to me.  I'd say we have about fifteen minutes to deal with this whole situation," said Marty.

"Why only fifteen minutes?" asked Jake.

"Because there is a certain tow-truck dragging a certain DeLorean behind it this way.  Inside the DeLorean are two very familiar people who if they see us could somehow alter the timeline," said Marty.

"That's right.  We can't allow our earlier selves to see us," said Doc.

"Funny isn't it.  Marty's earlier self is only a couple weeks old while Doc's is several years old.  I hate the fourth dimension!  I just hate it!" exclaimed Jake.

"You're the one who built these time machines," said Marty.

"Yeah.  I never learn," said Jake.

"Heads up.  There they are," said Doc.  Two cars were spotted on the road.  The Lamborghini was moving all over the place around Biff's car.

"What's she doing?" asked Marty.

"Trying to make Biff loose concentration and crash.  This provides us with an opportunity to slip in and steal the book," said Doc.

"How?" Marty asked.  Doc reached between his seat and the door and pulled out a hoverboard.

"Sarah was in a hurry and she left this behind," said Doc.

"Lucky us," said Marty.

"What's wrong?" asked Jake.

"I have this sense of déjà vu, and in this case I don't want to have it.  Trying to get that book from him really tired me out.  I'm not exactly anxious to do it again," said Marty.

"Yeah well too bad," said Jake.  Doc chuckled.

"You constantly surprise me.  You're nothing like Doc," said Marty strapping on the hoverboard.  Jake shrugged.

"It happens," he said.  The DeLorean eased forward barely above the ground towards Biff's car.  Biff was too focused on the Lamborghini to notice Marty grab a hold of his rear bumper and then the DeLorean fly off.  Biff drove forward to the tunnel and the Lamborghini zoomed forward and landed at the other end, facing Biff.  Biff stopped the car and gunned the engine.

"Chicken it is," he said.  Biff slammed his foot on the accelerator and zoomed forward as Sarah did the same.  The two cars raced towards each other as Marty hung on for dear life.  He then started to make his way forward along the driver's side of the car.  He was right next to Biff when the cars were only a few feet away from impact.  Marty stood up on the hoverboard and slugged Biff.  Biff temporarily lost control of the car and it drove off and scrapped the tunnel wall.

"You've screwed me for the last time!" exclaimed Biff.  He then drove the car towards the other wall.  Marty slipped the hoverboard up against the tunnel wall.

"So predictable Biff," said Marty as he slipped up and over the dash.  But before he could grab the book, Biff slammed the brakes and Marty went flying over the windshield and hit the pavement in front of the car.

"So are you kid," said Biff.  Biff was about to go towards Marty when the tires were blown out on his car.  Biff looked behind him and saw Sarah and the Lamborghini nearby.  Sarah chucked the rifle into the Lamborghini and faced Biff.

"Do you have the guts to face me?" she asked.  Biff laughed.

"I wouldn't hit a lady but in your case I'll make an exception," he said.  Biff rushed at Sarah who kicked him in the stomach causing him to fall on his back.  He slammed into the car causing the book on the dash to fall off to the pavement below.  Sarah then sat near Biff and started chocking him.  Marty leapt on her to get her off to him but Sarah merely swatted away like a fly.  Marty landed hard on the pavement but his head landed on something soft.  Marty pulled the Sports Book from behind his head and flipped through it to be sure it was the book.  Marty saw Sarah reach inside the Lamborghini and pull out the rifle.  She quickly aimed the rifle and fired only to hear the clicking sound indicating an empty chamber.  Sarah growled and sat back down in the Lamborghini searching for a single bullet.  Marty knew he had little time since Biff lay unconscious on the ground nearby.  Marty reached up and grabbed a hold of the door latch on Biff's car.  He opened the door and crawled up into the drivers seat.  He sat down and looked around for a match to light the book on fire.  He didn't notice any matches or anything that could incinerate the book and he knew that tearing it up would be pointless because all Biff needed was a single statistic and he could still change the future.  Marty looked around him in desperation and noticed the keys still in the ignition.  He saw that the car was pointed towards the wall and knew there was only one thing to do.  Marty slapped the book on the passenger seat and gunned the engine.  The car leapt forward and zoomed towards the wall.  Sarah meanwhile had found a bullet and loaded it into the chamber.  She then stood up beside the car and aimed the gun at Biff.  She placed her hand on the trigger.  Marty leapt from the car as it slammed into the wall and exploded.  Sarah's hand had pulled the trigger back halfway and was ready to pull it back the whole way when she was struck with a massive headache.  She dropped the gun and it fired sending a bullet flying off and harmlessly hitting the wall of the tunnel.  Sarah dropped down on her knees and bent over holding her head in pain.  She growled in pain before falling over on her side.  Marty stood up weakly and looked at the destruction of the car, Sarah on the ground, and Biff still alive.  Marty breathed a sigh of relief and walked over to Sarah.  He crouched beside her and tapped her shoulder.

"Sarah.  You okay?" Marty asked.  Sarah sat up propping herself against the Lamborghini.

"Fine.  I'll just have a little headache but it'll go away.  What happened?" she asked.  Sarah looked at the situation around her.

"Never mind.  I know.  Temporal psychosis," said Sarah.

"Yep.  Were you aware of what happened?" asked Marty.

"When I'm in Temporal Psychosis I loose all inhibitions.  I can't stop what I'm doing because I've lost all sense of morals.  It's not fun," Sarah responded.

"Has it happened often?" asked Marty.  Sarah shrugged.

"A handful of times I suppose.  One time I even hunted down Jake," she said.  Sarah briefly chuckled and looked around at the destruction.  The sound of an engine and a breeze indicated the DeLorean landing behind them.  Jake and Doc walked out.

"I don't know how we're going to fix this," said Doc.

"It's no problem," said Jake.  Jake walked over to the Lamborghini and pulled out a box.  He walked over to Biff and attached to electrodes to his head with wires that led to the box.  Jake pressed a few buttons and removed the electrodes.  Jake finally put the device back in the Lamborghini.

"Biff will have no idea as to what happened over the past few days.  Jake just erased his memory," said Sarah.

"That's not ethical," said Doc.  Sarah shrugged.

"Neither is time travel.  Besides.  Do you want to explain to Biff what just happened and make him forget it naturally.  That won't happen.  It's for the best this way," she said.

"I'll discuss this later with Jake.  In the meantime we'd better get out of here.  Marty and I will be driving through this tunnel in about three minutes," said Doc.

"What about Biff?" Marty asked.

"I have an idea," said Sarah.

Three minutes later: "Check that out," said Marty.  The tow truck towing the DeLorean stopped next to Biff's car.  The Lamborghini with it's back covered stood next to the other wall.  Sarah walked up to them with Jake.

"Hi.  We had a little accident but we're fine.  The police have been notified.  You can go," said Sarah.  Marty and Doc shrugged.

"Fine by me.  The car we're towing is part of a science experiment," said Doc.

"Okay.  Have a nice day.  Maybe we'll see each other some time," said Jake.  Doc shrugged.

"Maybe," said Doc.  The tow truck headed off down the tunnel dragging the DeLorean behind it.  After it had disappeared three sonic booms resounded in the tunnel.  The other DeLorean appeared and came to a screeching halt.  The doors opened and Marty dragged Biff to the same place they'd picked him up from.  Jake removed the tarp from the Lamborghini and folded it up before placing it the Lamborghini.

"How do we contact the cops?" asked Marty.  Sarah reached into her pocket and flipped out her cellphone.  She dialed 911.

"Hi.  I was traveling down the road underneath the tunnel to the southwest of Hill Valley and I discovered a car had rammed into the wall.  The passenger is unharmed.  Please send some help.  Thanks," said Sarah.  She flipped the phone closed and put it away.

"How does that work?  Doesn't it need a satellite to bounce off of?" asked Doc.

"I fixed it so that it doesn't need a satellite for short distances.  You can't call D.C. from here, but you can call L.A.  It helps cut down on contact with different time periods," said Jake.

"Fine.  Now let's get going before something else happens," said Marty.  Jake and Doc nodded and they boarded the Lamborghini and DeLorean and flew into the future.

2015: Six sonic booms sounded in the skies above as two cars appeared out of nowhere and soared down the skyway.  The traffic was extremely light at the time of night so no one really noticed the two cars appearance.  The Lamborghini and DeLorean soared along the skyway towards Crescent City.  They landed and parked inside Jake's garage just as the sun rose.  Jake pulled out his laptop and set it on his desk.  He checked the temporal status.

"99.9% return to normal.  The only things that changed were probably just Marty and Doc getting to the Library a little bit late but other than that nothing changed," said Jake.

"I'd like to bid you farewell.  Goodbye," said Doc.  He and Marty nodded, boarded the train, and took off.  The newspaper arrived and Jake picked it up and read it.

"Sarah," said Jake annoyed.

"What?" she asked.  Jake pointed to a headline.  The headline read: 60th Anniversary of the Invention of the Hoverboard.

"Oops.  That would have been the one Marty was using.  I'll be right back," said Sarah.  She boarded the Lamborghini and it soared off.  When she returned the timeline was back to normal.

"Good," said Jake as the headline talked about politics.

"I'm going home.  I need some rest," said Sarah.  She grabbed her hoverboard and went home.

"Good morning," said her father.

"I'm tired.  I'm going to bed," said Sarah.  Her father chuckled.

"Yeah.  Jake had me up on a few restless nights also.  Oh well, have a good rest," said her father.  Sarah went to her room and slept peacefully.