In a motion picture that has done away with the careful plotting and sharp characterizations of "Austin Powers: International Man of Mystery," the premise belonging to "Austin Powers in Goldmember" is so flimsy as to be hardly worth the space it will take to write about it. When shaggadelic British spy Austin Powers (Mike Myers) learns of a plot teaming arch-nemesis Dr. Evil (Mike Myers) with a repulsive 1970's-era disco king named Goldmember (Mike Myers, again) that involves crashing a gold asteroid into the Earth, Powers enlists in the help of sassy old flame Foxy Cleopatra (Beyoncé Knowles). The stakes are raised even higher with Austin discovers his equally randy father, Nigel Powers (Michael Caine), has been kidnapped.

"Austin Powers in Goldmember," from returning director Jay Roach (2000's "Meet the Parents"), is but a long series of humorous sketch ideas padded out by an uninvolving storyline. Granted, most fans of the series are more interested in simply being entertained than following a carefully defined plot with three-dimensional characters, but something feels terribly off about this sequel. Lead character Austin Powers has all but lost his raging sexual libido, as well as much of his endearingly shallow personality. New female sidekick Foxy Cleopatra is, by far, the most underwritten and boring of the Powers girls, and newcomer Beyoncé Knowles (of the music group Destiny's Child) pales in comparison to Elizabeth Hurley and Heather Graham. Knowles, who has little to do but spout off one-liners inspired by blaxploitation icon Pam Grier, gives a strictly amateurish performance that is almost, but not quite, as unfortunate as Mariah Carey's embarrassing turn in 2001's "Glitter."

Who is at the top of his game is Mike Myers, playing four different roles this time around (that of Austin Powers, Dr. Evil, Goldmember, and the self-explanatory Fat Bastard). Myers' superb comic timing and wondrous ability to transform himself into such wildly diverse characters is stunning. Ultimately, he is let down by his own screenplay, co-written by Michael McCullers, which more or less recycles the very same gags of the previous two films with various degrees of success.

Some comic set-pieces truly bring the house down, including an opening scene involving an endless array of big-name cameos that has to be seen to be believed; a run-in with a urinating water fountain statue; and a hospital drape silhouetting the goings-on of Austin Powers and pint-sized Dr. Evil clone, Mini-Mi (standout Verne Troyer), that hilariously misconstrues what they are really doing.

For every show-stopping moment, however, there are at least a half-dozen failed attempts. The seemingly constant jokes directed at new Austin Powers aide Number 3 (Fred Savage), who has a giant mole on his face, wears thin real quick, while the continued feuding between Dr. Evil and neglected son Scott (Seth Green) is a tedious example of just how unfunny the movie can be.

True to form, "Austin Powers in Goldmember" has many of the stand-by characteristics of the franchise: the farcical song-and-dance numbers; the spy movie take-offs; and the sexual-oriented and bodily function gags. At the same time, the romance between Austin and Foxy is undernourished and forced, with almost no time dedicated to developing them as a couple, or even as individuals. For all of its moments of comic gold, the film has a rushed, almost joyless, undercurrent that brings the fun down a notch. When it comes to spoofing the spy genre, the recent "Undercover Brother" holds more insight, originality, and energy than "Austin Powers in Goldmember" could ever dream of obtaining.