Marty left disgusted with himself and went over to Doc Brown's house. Doc met him at the door all excited about a new invention. Marty went inside to see what he was up to this time. His inventions were always a little whacky and seldom worked, but Marty still enjoyed his company and often helped him check out his crazy theories.

"It's a time machine," Doc Brown said excitedly. "The idea came to me 25 years ago. I want to travel back to that very day but I need your help."

"Sure Doc," Marty said skeptically as they walked out to the garage. "Wow. A DeLorean. Where did you get...