Back to the Future Part II
Marty quickly figures out that the timeline has been changed, with Biff now a rich tycoon who made his fortune by betting on sports results since the 1950s. After learning that his mother Lorraine (Lea Thompson) is married to Biff against her will and his father George (Jeffrey Weissman) is dead, Marty works with Doc to figure out what happened; they realize that the elder Biff from 2015 stole the DeLorean in order to give the almanac to his younger self