It's 1983,  28 years after Doc helped Marty go back to the future (or present, w/e 1985 was)

(Marty and Jennifer accidentally bump into Doc Brown in the street)

Marty:  Oh I'm sorry sir

Doc:  …Marty, Marty Mcfly?

Marty: Um, yea?

Doc:  Great Scott!  

(Doc hugs marty)

Doc: I cant believe its finally you, I'v waited so long

Marty:  Do i know you!?

Doc: Of course not. We met in the fifties. Btw, how funny is it that Reagan's president.  I was all like "marty you son of a bitch" hahaha

Marty:  Ok yea we're gonna be going now

Doc: Noo! We gotta start being best friends! 

Marty: Yea no thanks

(Doc grabs Marty's vest)

Doc:  Are you crazy!? You're gonna cause a paradox!

Marty:  Jennifer get the police

Doc: Noo! omg.. umm. ok. Ill give you 5 thousand dollars if you meet me at lone pine mall in 2 years .

Marty: What!?

Doc: You have to Marty! The universe depends on it!

Marty: Idk, this is heavy doc

Doc:  Hahah omg thats right, you say that.  Aww isn't this fun?