In order to prevent a series of events that could ruin the McFly name for posterity, Marty and his girlfriend must go into the future to 2015 where he must tangle with a teen rogue named Griff, who's obviously the descendant of Biff, the first Future film's bully. Our hero gets a money-making brainstorm and buys a sports almanac but Brown won't let Marty take the sports results records back with him. Biff overhears the discussion and picks up the almanac - before taking the DeLorean back to 1955 and successfully betting his way into power, creating Biff world. McFly has to leap through three generations of time travel to save the planet.

A clever sequel by director Robert Zemeckis which takes a darker turn than the original - and which may be a little lost on the uninitiated. (1989)