Episode II: The Empire Strikes Back

“The board is set, and the pieces are moving.”

--Gandalf the White, The Lord of the Rings, JRR Tolkien

Any way you slice it, the sequel to The Star Wars, much like the final film, was going to open with an Imperial attack on the Rebels’ base of operations.

However, it’s likely that, originally, ESB was meant to open with Vader’s fleet attacking Yavin IV, before the Rebels managed to move their headquarters to a new planet unknown to the Empire. In this case, the sequel would take place mere weeks to months after the events of the first film.

(Lucas discussed the possibility of having the Rebel base be still situated on Yavin IV with Leigh Brackett in the story conferences of late 1977.)

Once the heroes escaped the doomed Rebel base, the plot of ESB would have diverged, based on whether the overall saga was to follow the 9-episode or the 12-episode plan.