Underworld, a "werewolves vs. vampires" film released in 2003, wasn't perfect, but despite its wan screenplay, director Len Wiseman got some fun out of a novel concept and showed skill at making a low-budget project look like a slick, horror/action movie with a much bigger cost. The same cannot be aid for Underworld: Evolution.

This disappointing sequel isn't as much fun as its predecessor and features an even worse script. What should have been the next chapter in a grand, sweeping franchise, marrying the horror genre with the style of The Matrix and continuing the epic story of two supernatural forces waging war on one another, is instead a two-hour trailer with editing that caused me to wonder if Hollywood thinks we all have the attention span of that squirrel from Hoodwinked.

When we last visited the Underworld universe, Selene (Kate Beckinsale), a vampire whose centuries-old existence was once dedicated to slaying Lycans (werewolves, in laymen's terms), walked off into the proverbial sunset with Michael (Scott Speedman), a regular guy who now finds himself in the incredibly awkward position of being a vampire/Lycan hybrid. After doing away with a vampire elder and most everyone else she once called fellow soldiers in their war against the werewolves, Selene is now on the run, Michael in tow, and both are working harder than ever to find out what other nasty little dealings the vampires were up to. At the same time, though, Marcus (Tony Curran), the first bloodsucker of them all, awakens from his slumber and is none too pleased to see vampire corpses littering the mansion built upon his tomb. For some reason the filmmakers never bother explaining too well, Marcus sets out on a mission to free his twin brother,  the original Lycan, which inspires Selene to don her famous leather jumpsuit and load up on ammo one more time in order to stop the spread of new hybrid monsters once and for all.

If my plot summary for Underworld: Evolution seems a bit on the sketchy side, that would be the fault of the filmmakers. Because style definitely triumphed over substance in the first Underworld, Wiseman apparently decided to leave the story somewhere on his coffee table and to turn the style knob up to 11. As a result, Underworld: Evolution plays out a series of half-baked situations that provide the characters with an excuse to shoot something or chomp someone, all of which are strung out in an order one could only technically refer to as a "story."

Still, Underworld: Evolution does look pretty good, with dark, foreboding locales filling every inch of the screen, providing ample space for monsters to jump through the shadows. There's also an amped-up ferocity here, a tendency to emphasize the violence and monster-induced carnage that contrasts with the more slick, "guns 'n' leather" approach of the last film -- and this captured my interest, at least sporadically. The first scene, set in the early days of the vampire/Lycan war, has no trouble dropping viewers right into the brutal atmosphere that permeates most of the film.

But what nearly cripples Underworld: Evolution is its amazing inability to provide even the smallest of plot threads to follow. Looking at the story structure, you'd think  Underworld: Evolution was written by a grade-schooler who  thought it would be cool to see vampires and werewolves fight each other. If there's a concrete story within this film, Wiseman doesn't let you see it. He's too busy assaulting the ears with nonstop gunplay and the eyes with editing straight from the ADD School of Filmmaking.

I dig gunfights, monsters, and take-charge heroines as much as the next Sigourney Weaver fan (Kate Beckinsale holds up amazingly well considering the downright crummy material she has to work with), but it's hard to have fun when you have no clue who's shooting who...or, in this case, who's tearing who into bloody little pieces. In the process, this causes many a solid actor, from Curran to Bill Nighy (Love Actually) to overact shamelessly as they try to overcome the lack of importance this script seems to place upon them.

I didn't ask much out of Underworld: Evolution. All I wanted was a darkly-lit, blood-soaked actioner -- but one that at least maintined my interest as it moved from Point A to Point B.  Unfortunately, if movies were forced to take a sobriety test, Underworld: Evolution couldn't walk a straight line to save its life.

MY RATING: * 1/2 (out of ****)

(Released by Screen Gems and rated "R' for pervasive strong violence and gore, some sexuality/nudity and language.)