The following events occurred on October 21.
- Timeline 2
- Timeline 3
- 4:29pm: Doc Brown, Marty McFly, and Jennifer Parker arrive in the future from 1985 in the DeLorean time machine.
- Doc reveals to Marty about his kids and the trouble they would endure if Marty does not stop them.
- Marty subs for his future son Marty Jr.
- Marty encounters Griff Tannen and turns down his proposal to rob the substation.
- Griff's gang chased Marty around the Courthouse Square.
- The gang is jailed for crashing into the Courthouse and changes the original history.
- Marty meets Terry and becomes inspired to purchase the Grays Sports Almanac.
- Doc releases Einstein from a suspended animation kennel.
- Doc discovers the almanac and disposes of it.
- Jennifer, assumed to be Old Jennifer is taken to Hilldale.
- Old Biff Tannen overhears their conversation, grabs the almanac and follows Doc and Marty to Hilldale in a taxi.
- Doc and Marty rescue Jennifer.
- Old Biff steals the DeLorean and travels to November 12, 1955
- Old Biff returns and due to changing history, begins to fade away from existence.
- Doc and Marty leave for 1985, only to later find out that it has become 1985-A.
- Drew gets his parts from DCR.