Beware when a new film insists on reminding you of its "first" onscreen pairing of star actors X and Y. Like Nigerian "investors" e-mailing strangers for their credit card number, it's the kind of scam that can leave you in the cold.

It's a clever way to divert your attention from the other parts of the film that might fizzle and flop. Think of Danny DeVito and Arnie in the subpar comedy "Twins," or the Bennifer tag team in the dud "Gigli." This year's edition couples kung fu fighters Jackie Chan and Jet Li in Rob Minkoff's "The Forbidden Kingdom," a promising adventure movie whose potential is sweep-kicked to the curb.

Minkoff has the charming "Lion King" and "Stuart Little" series under his belt, but he applies those same quaint sensibilities to what might have been stronger as an all-out martial-arts genre flick. The hokey but whimsical storyline (based loosely on a traditional Chinese legend) could've been a boon if it weren't so mired in John Fusco's unmemorable script.

Michael Angarano ("24," "Seabiscuit") is Jason, a wimpy South Bostonian who gets pushed around by the neighborhood gang. He's an avid martial arts DVD collector and finds a hangout in a slummy Chinatown pawnshop. The teen discovers that the store's aging proprietor, Old Hop (a heavily powdered Jackie Chan), has an ancient sword in the back room with powers untold. When the bullies decide one night to rob the shop, Jason defends himself with the magical instrument. Then, at the brink of death, he finds himself transported back to ancient China.

His troubles have only begun. Instead of dopey hoods from South Boston, he's confronted by the wicked Jade Warlord (Collin Chou), who has turned the all-loving Monkey King (Jet Li) into solid stone. Jason's mission is to set him free and restore order to civilization, but he first needs a lesson or two in kung fu vernacular.

Chan doubles as the wine-addled Lu Yan, who teaches young Jason those very skills he's long admired on those bootlegged DVDs. Along the way, they meet the Silent Monk (Jet Li, again) who delivers excitement in his every frame. Unfortunately, the principal female lead (Yifei Liu) is subjected to every eye-rolling stereotype as the submissive, grief-stricken Golden Sparrow, who plays sorrowful melodies on her lute-like instrument. Of course she naturally falls for the clumsy American hero.

Kung fu just isn't as much fun to experience when it feels like a synthetic video game. Rather than letting the natural flow of the action take over, extended slow-motion sequences dice it all up. In one rare comical scene, Chan tries to conjure up some raindrops in the desert, only to realize that Li is urinating on him. Then there are long, irritating stretches where characters want to wax contemplative and share phony, hoary truths. "Music is the bridge between Earth and heaven," says the straight-faced Golden Sparrow to Jason. This patchwork mess of slapstick, computer-generated Buddhist fantasy, Eastern epic, etc., doesn't ever quite allow viewers to happily abandon themselves to any of them.

-By Bryant Manning / Universal Press Syndicate