Calling Jet Li the Emperor in The Mummy: Tomb of the Dragon Emperor is accurate. Emperor has no credited last name. Just Emperor. Not even Dragon Emperor, although Emperor does, at one of many numbingly stupid plot points, morph into the slowest-flying dragon a film has ever seen.

If not for character continuity from far-superior modern Mummy movies, returning roles could simply be Hero, Heroine, Son, Uncle. And the new characters: Whiny Immortal, Facial Scar Lady or Dude With Arms Ripped Off in 50 B.C. Whose Skeleton Has Arms In 1947 A.D.

No one would confuse The Mummy or The Mummy Returns with classic cinema, but each had old-school serial thrills, modulated macabre and palpable heart and charm. Despite returning star Brendan Fraser’s spark, this sequel is soulless, loud, dull and aggressively unintelligent.

Where did the heroes get that second plane? Why must Emperor drink from the Pool of the Elixir of Eternal Life when, after he’s splashed with it like cologne, he breaks from his mummified prison? Questioning creature-feature logic usually is a buzzkill. Here, it’s essential to keep the brain from liquefying into the same diarrhea-looking goop as Li’s body does in the film’s prologue.

In a part no more substantial than The Rock in Returns, Li is a vicious Chinese ruler in 50 B.C. seeking immortality but tricked by a righteous witch (Michelle Yeoh). (By vicious, that means Li’s patented emotionless “villain” scowl.) Her curse turns Emperor and his army into terracotta statues often found on clearance at Pier One, buried beneath the sand and never to be resurrected.

Until 1947, that is, in which Alex O’Connell, the charming kid from Returns, has grown into a combination of Hayden Christensen, Richard Grieco and a popped-collar Delta Chi you want to sock in the jaw. Alex (a dismally untalented Luke Ford) is seeking Emperor’s remains for fame.

Meanwhile, Alex’s parents, Rick (Fraser) and Evie (Maria Bello, a poor stand-in for wisely absent Rachel Weisz), are stir-crazy at home in England. Paying a surprise visit to Alex in Shanghai — where Evie’s ne’er-do-well brother Jonathan (John Hannah) also resides — leads to the Emperor’s awakening, a journey to mythical Shangri-La and, for the lucky audience member, a two-hour nap.

By now, Fraser is the Brando of acting opposite computer-generated things that really aren’t there. Amid pygmy mummies and scorpion kings, the first two films at least had good action-ensemble acting. Here, Fraser has better rapport with green-screen balls than anyone with a pulse.

With a constant grin as idiotic as her British accent, Bello’s casting is a cruel joke, and she looks like a cross between Kate Beckinsale and Frances McDormand. No points for guessing which actress the usually stunning actress sadly emulates.

Playing Lin (aka Whiny Immortal), an assassin guarding against Emperor’s resurrection, Isabella Leong offers the most stereotypical Asian woman since Julia Nickson in Rambo: First Blood Part II. (There are 25-minute junior-high plays with better acting than the scenes with her and Ford.)

And a sampling of Hannah’s lines: “You guys are like mummy magnets!,” “I hate mummies!” “Die, you mummy (ingrates)! Die!” and “He yakked!” after being thrown up on by a yak. Get it?

Hannah also has a supreme eye-rolling moment — dropping a bomb from a plane onto a car not with any targeting system but with HIS BARE HANDS. This is after it takes but an overnight hike for the O’Connells to reach Shangri-La (which looks like plugged-in “moving” artwork at a Chinese buffet) and Tibetan yetis make field-goal symbols when dropkicking men between temple spires. (Surely not intended by writers Miles Millar and Alfred Gough or director Rob Cohen, Lin speaking to yetis is the funniest man-beast interaction since Anchorman: The Legend of Ron Burgundy.)

Speaking of Cohen, he often knows good B-material when he sees it (The Fast and the Furious, xXx), but he and his visual effects crew turn in hired-hand hackwork here.

One avalanche looks like large projectile Dippin’ Dots, and there must be Macs sold with built-in software allowing you, the home-computer user, to render your own CGI armies and soaring arrows. Here’s a title for the better movie you could make: Gloom of the Dragging Emperor.