On October 26, 1985, Dr. Emmett Brown arrives from the future and tells Marty McFly and his girlfriend Jennifer Parker that he needs their help to save their kids in the future. They depart in the flying DeLorean time machine as Biff Tannen accidentally witnesses the departure. They arrive on July 5, 2010, where Doc electronically hypnotizes Jennifer to sleep and leaves her unconscious in an alley to keep her away from his plan. Meanwhile, Doc has Marty pose as his son, Marty McFly, Jr., to refuse a robbery from Biff’s cybernetically enhanced grandson, Griff Tannen, which would result in the arrest of Marty Jr. and his sister Marlene for breaking him out of jail, and that these events would cause more downward turns for the McFly family. Marty refuses the deal, but Griff goads Marty into a fight; Marty escapes the fight and leads Griff and his gang on a hoverboard race across the courtyard square, ultimately resulting in Griff and his gang crashing through the courtyard windows and changing the future history as they are promptly arrested instead of Marty Jr. On his way back to meet with Doc, Marty purchases an almanac detailing results from major sporting events of the last half of the 20th century. Doc discovers the purchase and lectures Marty on trying to profit from time travel, but before Doc can dispose of the sports book, they are forced to follow the police who have found the sleeping Jennifer and are taking her to her future home. Old Biff, overhearing the conversation and recalling the DeLorean from 1985, follows with the discarded book.
Hoverboads? Cybernetic Enhancements?