It is a path that leads from the ultra-modern particle accelerator at CERN in Geneva through the millennia-old catacombs of Rome and into the heart of Vatican City. In The Da Vinci Code, Robert Langdon, an American expert on the meanings of symbols, irked Catholic Church officials as he deciphered messages from the ancient secret order Opus Dei; but this time the church has called him in to help solve a mystery that also involves a code hidden in art works from centuries ago as well as another shadowy group.

Dating back to Galileo, the secret brotherhood accuses Catholic leaders of suppressing science; so it is with no small irony that the conspiracy threatens the church with a deadly device using the newest technology.

Tom Hanks has previously resisted doing sequels to his hit movies, but the Oscar-winner says he welcomed the return to the Langdon character. There's a lot of high-octane action in Angels & Demons, but Hanks quips that some of the simpler scenes posed unexpected challenges.

"Just your average running in Rome is a hard thing to do," Hanks said. "There is not a regular cobblestone, not a straight step, not an easy way across any street in all of the 'Eternal City.' Essentially deathtraps and twisted ankles await you any time you try to move faster than a slow stroll. How we did not come out with shin splints and Ace bandages around our limbs I will never, ever know. It must have been divine intervention."

Director Ron Howard, who also helmed The Da Vinci Code, says church iconography is part of the "Angels and Demons" story; but getting it on film with little or no cooperation from the Vatican created some of his more vexing challenges.

"When you come to film in Rome the official statement to you is that the Vatican has no influence over Rome," explained Howard. "The permits that you receive are between you and the city of Rome; but unofficially, a couple of days before we were supposed to start filming it was explained to us that it would difficult for us to gain the kind of support that we needed if we wanted to shoot in a couple of areas where some particular churches were in the background. Normally, if you get your permit, it's okay to shoot (no matter what is in the background). I suppose we could have contested this. We didn't. We navigated that and made the movie and I think we successfully managed to take people on the "Angels and Demons" experience. That was my goal as the director."

A Catholic Church spokesman dismisses Howard's suggestion of Vatican interference calling it an attempt to boost publicity for the movie.

Director Howard acknowledges the plot of Angels & Demons contains elements some Catholics could find controversial, notably the conflict between Church teachings and some scientific research; however he adds that with novelist Brown, that is to be expected.

"I suppose that controversy and discussion, in a way, go hand in hand with what Dan writes …certainly in these two novels …and if it was completely absent in the movies I think something would be missing," Howard said.

For his part, the author hopes his work does spark debate, but he warns against believing everything in either The Da Vinci Code or Angels & Demons.

"These are fictional stories built around real world topics," noted Brown, "and it is my hope that they spark a lot of interest and research on peoples own to figure out what in these stories is fictional and what is real. I think the movie also does a terrific job of leaving you with a lot of those questions in the parking lot after the movie."
Scottish actor Ewan McGregor plays Camerlengo, the church official who works most closely with the Pope and who is a key element in the plot of Angels & Demons.

"I find the script really exciting," McGregor said. "It's like an old-fashioned thriller. The clock is ticking away and I find the character to be interesting so I was happy to be involved."

The international cast also features Israeli Ayelet Zurer as a particle physicist who helps Hanks' character solve the mystery. Italian screen star Pierfrancesco Favino is a detective in the Vatican police force; Sweden's Stellan Skarsgard plays the commander of the Swiss Guard charged with protecting the Pope; and German-born Armin Mueller-Stahl is a leading Cardinal clinging to the Church's traditions.