Only read the rest if you completly finished the "It's about Time" part. All the way to the credits.
If you are still reading you should know that Marty begins to dissapear like in Part 1. (Original Part 1(the movie)) And then it says that Marty goes back to 1931. I think it's because he gave the subpoena to his grandfather, so Kid Tannen kidnaps him or something and somehow makes Artie dissapear form existense. Or Judge Brown might think that Artie was a bad guy and make Artie dissapear from existence. But in the Synopis (http://www.telltalegames.com/bttf) it says that Kid might erase Jennifer fron the future. I'm not really sure how that happens. Maybe One of the gang members is her grandfather or her grandfather is another guy like Artie that gets pushed around by Kid. Say what you think will happen! :)
Edit: Alright, now we know Officer Parker is Jennifer's Grandpa, and Trixie Trotter is presumably the singer that dissapears. The Information was received by a Telltale email update thing.
Email as follows
"Following the blockbuster series premiere "It's About Time", the second episode of Back to the Future, "Get Tannen!" will be available for download on the PC and Mac this February. That means it's just a few short weeks until you can find out what happens in the second of five monthly chapters of Marty and Doc Brown's new adventure. You'll be able to get your first look at "Get Tannen!" in the official trailer, also coming soon.
We have a special treat for you, the faithful Interloper subscriber: We're pulling back the curtain on two of the characters that appear in "Get Tannen!", Officer Parker and Trixie Trotter. Officer Parker, Jennifer's granddad, is just a good cop caught up in a bad situation. On top of dealing with Kid Tannen and his goons, he also has a time-traveling duo causing him some problems. Trixie Trotter, on the other hand, is a small-town girl with big-city dreams. She may seem like just another mob moll, but she actually has aspirations for greatness.
What do you think is next for Doc and Marty? Speculate and discuss your theories in the comments of our "Get Tannen!" Predictions blog post and forum thread! Get on it butthead!"
We know that the singer dissapears because in one of the newspaper articles in Edna's house, it says a singer dissapears. Keep looking for clues! :D