The story is really convoluted, and that's perhaps my only real gripe. I don't think I ever fully made sense of the backstory, but I'll do the best I can to summarize it. Decades earlier, an alien named Serleena came to Earth in search of a mystical light that was hidden here. The light was launched into space by the MIB and our planet was saved from destruction. Now, Serleena returns to Earth in search of the light, believing it is still here. Upon its arrival, the alien assumes the form of a Victoria's Secret lingerie model (Lara Flynn Boyle). She knows that the key to finding her treasure lies in MIB Headquarters, which she promptly infiltrates. Assisting her is a two-headed alien, played by Johnny Knoxville of MTV's "Jackass." There's some talk about how - if the light is not found within a certain time frame - the Earth will be destroyed, but that is also a rather muddled plot point.

Will Smith returns as Agent Jay, who has unsuccessfully teamed with other partners since Agent Kay (Tommy Lee Jones) left the agency and had his memory erased at the end of the original movie. When MIB leader Zed (Rip Torn) finds out that Serleena is on the planet, he knows that Kay is the only one who can help; after all, he's the one who got rid of the light in the first place. Jay finds Kay working in a small-town post office and, in a clever plot reversal, now has to recruit him back into the organization. Meanwhile, Jay develops a romantic interest in Laura (Rosario Dawson), the only witness to one of Serleena's first acts of meyhem.

New hotness Will Smith reteams with Tommy Lee Jones for Men in Black II

Although I didn't really understand the whole thing about the light, I wasn't particularly bothered. After all, that's not the real story here. The story is Jay bringing Kay back into the fold. The smart thing about both movies is that they keep the emphasis on the main characters. Whereas Kay was the by-the-book mentor in the first film, Jay is now the mentor, and he takes a hipper approach. Notice the scene in which Jay compares his MIB vehicle ("the new hotness") to Kay's standard issue car ("old and busted"). That's the kind of thing we care about - the relationship between these two men who work for the most covert and secretive government organization possible. The screenplay builds on that idea, as Jay laments the loneliness of the job. The only person an MIB can relate to is another MIB.

As before, the movie also has fun with the conventions of the sci-fi genre. There are lots of jokes about who is really an alien and who merely seems like one but isn't. I also like the series' ongoing existential references to the fact that universes can exist within other universes. This takes shape in a running joke about a tiny colony of creatures that live in a bus station locker. The bigger set pieces are wonderfully wacky too, especially the one involving a giant worm running through the subway system.

Men in Black II made me laugh a lot, but there were three things that elicited real belly laughs. I won't ruin the jokes, but I'll tell you where to look. 1.) a household name celebrity begs to join the ranks of the MIB; 2.) Frank the Pug, returning from the original, sings along to a well-known novelty song on the radio; and 3.) a scene showing an alien race known as the Balchinians, who have to be seen to be believed.

It's worth noting that director Barry Sonnenfeld gives the movie a uniquely quirky feel that perfectly suits the material. He once again avoids the temptation to turn the finale into an overblown special effects extravaganza (one of the things I admired most about the first film). The ending is all about Jay and Kay, and it pulls things together in a way that is consistent with their characters.

Because the characters matter, it's essential that the actors matter too, and they do. Will Smith and Tommy Lee Jones are perfectly cast. They are one of the great screen duos and, in this installment, seem to be having fun turning the mentor/protégé tables. The fun is infectious. Men in Black II is the rare sequel that makes me yearn for a Part III.

( 1/2 out of four)

Men in Black II is rated PG-13 for sci-fi action violence and some provocative humor. The running time is 1 hour and 28 minutes.