"Same planet. New scum" smirks the tagline for the return of Barry Sonnenfeld's alien-busting crime fighters. Catchy, eh? But the marketeers might as well have added "Same movie", for "MiB II" sticks true to the timeworn studio mandate for blockbuster sequels: Remake the first one. But not as good.

A sleeper hit in 1997, "MiB" was a slick blend of James Bond cool, 50s monster movies, and X-Files paranoia. Plus it boasted the improbably successful double act of streetsmart Philly rapper Will Smith and professional Texan grump Tommy Lee Jones - as Agents J and K, the wisecracking, shade-sporting, smart-suited, protectors of the Earth from the scum of the universe. This was sci-fi it was OK to like: geek chic.

Second spin and the roles - J the rookie, K the veteran - are reversed, as Smith must retrieve his ex-partner from the mind-wiped obscurity where part one left him. Turns out that, just as in the original there's a planet-threatening MacGuffin which they must get off the earth and its location is buried deep in K's memory banks.

So far, so so. Plot smot. We want aliens! We want jokes! We want action! And we get it all - it just lacks spark. Despite a five year break between movies, "MiB II" was rushed into production ahead of last year's threatened actors' strike and it shows. Smith and Jones gamely try and work with a script that was being written as they filmed - but while the publicity for the movie has trumpeted the return of the whole original team, one man is missing: writer Ed Solomon.

With the plot misfiring and the stars struggling, it's left to small mercies to save the movie: a beefed up role for smart-mouthed dog-shaped alien Frank the Pug; Rosario Dawson's love interest; Lara Flynn Boyle's breasts.

"MiB" fans prepare to be whelmed: this is effective button-pushing sci-fi entertainment, but you won't need to be neurolized to forget it.