Marty McFly had kept the parts to the old Dalorean. He kept it as a souvenir. As the years went by, he married Jennifer and they had two kids, one of them named after Marty. Marty Jr. had heard all about the time machine, that was supposedly made of the parts of the old Dalorean.

Over the years, Marty Jr. secretly worked to reconstruct the old Dalorean. He also was beaten up on a lot by Biff's grandson, Griff. He hoped to go back to the past and stop Griff from being born, as he so disliked Griff.

"You're so dumb McFly!" shouted Griff, who had flicked Marty Jr. on the nose when he had tricked him into looking down.

"Leave him alone Griff!" shouted Erin, who was Marty Jr.'s girlfriend.

"Your man is such a wuss!" laughed Griff.

At last, one night around when he was 17, nerdy Marty Jr. had finished reconstructing the Dalorean.

"It's finished Erin. Now I can go back in time and stop Griff from being born!" said Marty Jr.

"I know your father talks of a time machine, but I think he's just making it up." said Erin, shaking her head.

"No, I found old Doc Brown's notes and papers. It's real." said Marty Jr.

"If you say so." said Erin skeptically.

"Come on and let's give it a test. It should work on just regular trash." Marty Jr. said to Erin.

The two got in. "We need to get to 88 miles per hour!" Marty Jr. told her. They got in and took off. However, as they started to reach 60, Griff drove his car toward them.

"Out of the way McFly!" he shouted.

Marty Jr. was able to avoid him, but accidentally bumped the time period button. He accidentally set it for the time between the Jurassic and the Creataceous. They went through time as they hit 88 miles per hour. When they reappeared, they were near the Great Valley. They saw dinosaurs.

"This isn't right." said Marty Jr.

"What happened?" asked Erin.

Marty Jr. noticed that it said 20 million BC. "We went back to the time of the dinosaurs!" he yelled in horror.