Head back to 1955 and stop Biff
From Create Your Own Story
You have Marty go after the Almanac while you set about repairing the time circuits. You advise Marty to wait until Old Biff is gone before taking the Almanac so he would go back to the future with the DeLorean. During the repairs, you notice the destination time keeps resetting to January 1, 1885. Eventually you get a call from Marty. He failed to get the Alamanac from Young Biff and is trapped in his garage.
