Marty McFly and Doc Brown leap into the future of 2015, only to create a corrupted alternate 1985 ruled by Biff Tannen. To restore the timeline, they must revisit 1955 and dodge their own past selves. Packed with time-travel paradoxes, dystopian alternate realities, and teen comedy twists, this sequel expands the iconic mix of sci-fi spectacle and quirky humor into a darker, mind-bending adventure.

Från IMDB:
After visiting 2015, Marty McFly must repeat his visit to 1955 to prevent disastrous changes to 1985...without interfering with his first trip.