Dan Brown gets a bad rap for his unique brand of beach-reading literature, but maybe he just should have been born 60 years earlier. If his work was going to be turned into cinema, it really should have been for 1930s serials.

Just think about it: Both The Da Vinci Code and its published prequel/filmed sequel Angels & Demons abandon all pretense of character development in favor of pure plot mechanics; every chapter is anchored to a cliffhanger more cliff-hanging—and more preposterous—than the last. If some screenwriter and/or director simply treated them as the narrative junk food they are, his stories might be tremendous fun. But it seems as though the inclusion of religious iconography and heterodoxical "history" has made Ron Howard and his collaborators—and, frankly, all those getting so hot and bothered over their content—take them far too seriously. If you thought Howard's adaptation of The Da Vinci Code managed to make ecclesiastical conspiracy boring, just wait for Angels & Demons.

Tom Hanks—sans his greasy Da Vinci mullet—is back as Harvard symbologist Robert Langdon, summoned by Vatican officials to help deal with a potential crisis. Though the book was written before Da Vinci, a few knowing references here make it clear that the events in the movie post-date Da Vinci, and therefore the Church understands that Langdon knows his stuff. In the wake of the death of the Pope, the four cardinals who are the primary candidates to replace him have been kidnapped. Evidence suggests the involvement of the Illuminati—the ancient society of scholars and artists whose pro-science views antagonized the Renaissance-era Catholic Church. And if Langdon can't follow the clues to the lair of the Illuminati, the Vatican itself could be destroyed by a cylinder of stolen anti-matter.

It's somewhat fitting that in Angels & Demons, the greatest threat comes from something representing the complete absence of substance. Langdon has the potential to be a really entertaining character—a true, non-Indiana Jones academic thrust into life-threatening situations—but nobody involved appears the slightest bit interested in exploring that character. Hanks is once again stripped of his likeability, furrowing his brow and scowling as though he's embarrassed to be a part of the thing even as he's filming it. And they manage to find an even less interesting female counterpart in Vittoria Vetra (Ayelet Zurer), a physicist whose personality begins and ends with her ability to spout all the necessary tech-babble about the threat posed by the anti-matter. As was true in Da Vinci, Howard simply allows Langdon's puzzle-solving to carry us from one place to the next, like some life-or-death scavenger hunt.

That's when things get really excruciating. It's one thing to build a suspense thriller around a ticking clock to some potentially horrible event. Angels & Demons piles up five or six such will-they-get-there-in-time perils, which might have been at least somewhat enjoyable if played lightly. Yet here, with the incessant ominous music and obligatory choral screeching—because, you know, Catholicism is involved—the over-the-top scenarios are treated with a ritualistic somberness that makes a Latin Mass seem like prom night by comparison.

As for whether or not Angels & Demons stomps on the sensibilities of the faithful, it's certainly more generous than The Da Vinci Code. This one asks a few fairly interesting questions about the interplay between science and faith, with an apparent battle for the Church's future between an old-school cardinal (Armin Mueller-Stahl) and the deceased Pope's young counselor (Ewan McGregor). But treating its themes with too much gravity is part of the problem in the first place. Whatever its thoughts on religious authority, let's not forget that Angels & Demons is a movie about people racing around Rome trying to prevent an anti-matter explosion.

There's a fleeting moment—near the end, and far too late—when Howard almost sees what this series could have been. As the cardinals make their crucial vote on who will be the next Pontiff, Howard tracks along the Pope-announcing Vatican chimney through the building towards the rooftop smoke, the score pounding as though we were watching the fuse of a bomb. Give me that kind of silliness, with all its attendant guilty pleasures, rather than watching the smudgy smoke rising from this dud.

ANGELS & DEMONS

*1/2 (one and a half out of four stars)

Directed by Ron Howard

Starring: Tom Hanks, Ayelet Zurer, Ewan McGregor

Rated PG-13.