The Purpose Of Their Trip
It all started with a science experiment in Back to the Future, which saw Doc Brown testing his time machine to see if it’d work. But then, Marty McFly accidentally goes back to 1955, and has to correct the mistake of throwing off his parent’s first meeting and falling in love. That’s a simple enough beginning, but then Marty has a double shot of intentional time travel adventures, as Back to the Future Part II starts with Doc bringing Marty and Jennifer to 2015 to save their kids from going to jail, but leads to having to correct old Biff Tannen’s betting streak starting in 1955, and preventing Doc from being murdered by Mad Dog Tannen in 1885. Last, but not least, Marty has to go home to 1985 when all is said and done; because the time continuum.