In Back to the future (part 1), it's the mid-80's, and Marty McFly is your average 17-year-old slacker who happens to be friends with an inventor, Doc Brown. Doc's latest invention is a time machine, that ends up transporting Mary back to 1955 where he must bring get his parents together so that he will exist when he gets back to his own time. In Back to the future II, Marty visits 2015 to straighten out the future of the McFly family, but Biff Tannen steals the time machine, and with it a book that allows him to amass a gambling fortune, which has significant consequences to the present. Marty and Doc must return to 1955 to retrieve the book. In Back to the future III Doc Brown has decided to live in the Old West of the 1880's. But when he's in danger of meeting an untimely end, Marty travels back into the past to rescue him. Doc is so smitten by a schoolteacher that he's become distracted. Now, it's up to Marty to keep Doc out of trouble, get the DeLorean running, and put the past, present and future on track.