I haven't seen the previous two movies in the Mummy series, although people have recommended them to me as rollicking old-fashioned action-adventure movies, from the same Saturday-afternoon-matinee roots as the Indiana Jones series -- not exactly brain teasers, but good silly fun. The good news is that if you too haven't seen the preceding movies, you can watch The Mummy: Tomb of the Dragon Emperor without fear of getting confused or lost or not understanding the recurring characters. The bad news is that regardless of whether you've watched the other films, the third Mummy entry is a headache-inducing mess that piles on unimpressive special effects to stretch a slight and often incomprehensible storyline.

The movie begins with an extended backstory: the history of the Dragon Emperor from thousands of years ago, in which a ruthless tyrant (Jet Li) bargained with an infamous witch (Michelle Yeoh) in his ambitious drive to seek immortality. The backstory, narrated in a manner befitting the History Channel, goes on for far longer than necessary. (Hellboy II did this so much better and faster, and with cool puppetry too.) It's a full 10 minutes before the story begins and we encounter the leads from the previous Mummy films, Rick O'Connell (Brendan Fraser) and his wife Evelyn (Maria Bello this go-round), who have retired from the action business and are trying to lead humdrum lives in the English countryside.

However, they're lured back into their Nick-and-Nora-wannabe roles to deliver an artifact to China, where their grown-up son Alex (Luke Ford) is secretly excavating an ancient emperor's tomb ... guess whose tomb that might be? Of course there's a curse, and a giant diamond, and Evelyn's brother Jonathan (John Hannah) from the previous two films just happens to be running an Egyptian-themed nightclub in Shanghai so he's pulled back into the action too. Next thing you know, the whole crowd is out to stop the ancient Emperor mummy (who is more like one of the cursed Pirates of the Caribbean characters than a traditionally embalmed mummy) from regaining all his powers of immortality and raising his invincible golden clay army that will take over the world.

The movie tries to entertain us with a series of daring escapades and breathtaking spectacles, but unfortunately these attempts fall far short of their aspirations. A long chase sequence across Shanghai during Chinese New Year is meant to be a breakneck adventure, but the camera careens so wildly and awkwardly that I lost track of the action -- wait, where did Rick go? What's that the emperor is throwing ... bits of his face? Later in the film, the CGI effects descend upon the storyline with a vengeance, and everything looks so similar and so fake that when a character exclaims "Shangri-La!" you want to murmur, "it's only a model." And let's not discuss the eyeroll-inducing CGI Yeti.

But the CGI isn't the weakest and most damaging part of The Mummy: Tomb of the Dragon Emperor -- that honor goes to the screenplay. The actors sell the dialogue as capably as they can, trying to emulate the snappy lines and easy wit of 1930s romantic comedies or at least classic action films. Unfortunately, the lines are so trite and dumb and unfunny that they elicit puzzlement rather than humor. Even Maria Bello's Emma Peel-like delivery can't save these lines. The film also relies on jokes that are just plain dumb, like a barfing yak. Other moments that might be funny with the right timing often fly by in the middle of one of the frenetic action sequences and we don't get time to register the gag, much less to laugh.

During the film's climactic fight scenes, as CGI tepidly battles CGI, one scene lights up the screen briefly. Jet Li and Michelle Yeoh's encounter involves no computer-generated creatures, and is shot not at hyperspeed but in slow motion. The exaggerated motions a la Crouching Tiger, Hidden Dragon seem positively organic in comparison to the rest of the film. It's a lovely moment ... and then we cut to more cliched one-liners and uninspired effects. I don't understand why you'd cast Jet Li in a role that wastes his great screen presence by covering him in bad special effects most of the time, when he's far more compelling in his own skin. In fact, I would love to see the entire cast in a better movie with a stronger script.

It's hard not to compare this movie to Hellboy II for more reasons than the similar prologues, which made me wish I could sneak over to an adjacent theater and watch the Guillermo del Toro film again. Both movies are about a villain who intends to unleash an invincible inhuman army upon the world. However, the elf-prince in Hellboy II at least seems to have an understandable reason. Both movies feature main characters trying to sort out relationship problems at the same time they're battling forces of evil. But the difference there is key -- the characters in Hellboy II had more emotional depth, and their relationships with each other and with humanity were what ultimately drove the film. In The Mummy: Tomb of the Dragon Emperor, the characters are glorified cardboard cutouts, and it's hard to care about why they're all bickering -- the action of the film doesn't reflect or tie into the emotional conflicts.

At the screening I attended for The Mummy: Tomb of the Dragon Emperor, one person in my row seemed to be enjoying himself thoroughly in the audience: a five-year-old who hadn't seen enough good action-adventure films to feel jaded by this tired retread. But if you're too old for kindergarten, you might want to skip this movie and catch Hellboy II instead. Or rent a good Jet Li film, or even revisit Raiders of the Lost Ark. I've been pleasantly surprised by a number of films this summer that were more fun than I might have expected, but this movie was an unfortunate letdown.