Three is the hardest number. Francis Coppola tripped on it ( The Godfather Part III). So did George Lucas ( Return of the Jedi) and David Fincher ( Alien 3) and Sam Raimi ( Spider-Man 3) and the Wachowski brothers ( The Matrix Revolutions). Peter Jackson pulled it off with The Lord of the Rings, but all of those movies came from the same book and were shot back-to-back.

One of the most striking things about The Dark Knight Rises, the third entry in director Christopher Nolan’s trilogy of Batman movies, is how bold and confident and precise it is — as if the filmmaker had always known how the story that started in 2005’s Batman Begins and continued in 2008’s The Dark Knight would turn out.

The truth is, Nolan was making it up as he went along.

“I’ve always thought of this trilogy as Bruce Wayne’s story, and every story has a beginning, a middle and an end,” he says. “The ending is the most important part to me: That’s the first thing I had for The Dark Knight Rises. The trick is to know it on a subliminal level — have the idea of it — but not write it down and make it concrete until you’re ready.

“I’ve had the great luxury of working on these movies for nine years and letting things grow naturally, knowing the feeling of what I was going for but allowing the narrative to come into focus over time. You have to live your way through stories in order to discover what they are. I wasn’t already planning for this movie when we were making Batman Begins, because I’m superstitious. But I was always hopeful I’d get to tell the whole thing.”

Set eight years after The Dark Knight, the new film, which opens Friday, catches up with millionaire Bruce Wayne (Christian Bale) as his fortune is dwindling, his body is battered (he has a permanent limp and walks with a cane) and his alter-ego of Batman is still at large and wanted for the murder of Harvey Dent (played in the previous movie by Aaron Eckhart).

The crime rate in Gotham City has plummeted under the watch of Commissioner Jim Gordon (Gary Oldman), who continues to feed the lie that Dent died a hero, using him as a martyr to help keep the peace. Then the terrorist Bane (Tom Hardy), a masked thug with a penchant for brutal violence, emerges from the city’s sewers. He brings an army with him.

The Dark Knight Rises borrows elements from two classic Batman comic-book storylines — Knightfall, in which Bane snaps the hero’s back, and The Dark Knight Returns, Frank Miller’s seminal graphic novel about an aging Batman forced out of retirement by a crime wave. But the film’s screenplay, which Nolan wrote with his brother (and frequent collaborator) Jonathan, charts its own narrative path, throwing in a curvaceous cat-burglar (Anne Hathaway), an idealistic police officer (Joseph Gordon-Levitt) and a philanthropist (Marion Cotillard) who helps Wayne with his struggling finances.

When the $250 million production began shooting, the large number of new characters concerned fans, who speculated that Nolan might have fallen prey to the “more is more” approach that had mired the 1990s Batman film franchise in campy excess.

“The third movie in every trilogy is supposed to go into the toilet,” says Michael Caine, who reprises his role in The Dark Knight Rises as Wayne’s faithful butler Alfred. “But when I read the script for this one, I knew it would be special — and I’m not just saying that because I’m in the movie! Christopher [Nolan] is an incredible caster of actors, he’s an incredible director and he’s also an incredible writer. He’s all three of those things, and that’s something I’ve never encountered before in this business.”