McCallum read the completed script only 10 days before production started and agrees with Lucas's summary. "It is a darker film and it's much more complex emotionally," he says. "Everybody knows Anakin Skywalker has to turn into Darth Vader, we just don't know the how and the why of it. That's what drives the drama of this one."
As for keeping the ending a secret . . . well, the finale to Episode III was revealed in 1977 in the original film, Star Wars: A New Hope (Episode IV in the saga): Skywalker betrays the Jedi Order and hunts down and murders the remaining Jedi Knights; Padme Amidala, Skywalker's wife, gives birth to twins, Luke and Leia, but they are hidden from their father for their protection; Skywalker suffers serious injuries after a battle with Obi-Wan Kenobi and he becomes more machine than man in his recovery, to complete his transformation into the evil Darth Vader.
"We are hoping it will be the shortest of all of them but it will probably end up at about exactly the same time two hours and 10 minutes," he says.
"This is about not really moving from II to III, this is about linking III to IV and tying up all the loose ends. So somebody who doesn't understand Star Wars can start with Episode I and follow the whole saga, the whole family all the way through. Personally, I think this is the coolest of the lot but I also thought that about Episode I and II."