This sequel picks up where the original 2003 Underworld left off with a continuing war between the vampires and the werewolves.
Underworld: Evolution is directed by Len Wiseman, husband to Kate Beckinsale, who plays Selene, the vampire warrior. A background story helps to explain why Selene is a one woman/vampire revenge machine, but doesn't do enough to clear up a number of questions.
Bill Nighy plays the vampire's leader, Viktor and Scott Speedman is Michael, a hybrid werewolf and Selene's love interest.
There's plenty of violence and gore with heads sliced off, swords run through the heart and various other gross killings. The makeup and special effects have improved, but there aren't any truly good action sequences.
A beginning scene where werewolves are slain and then set on fire before they can "change" is muddled and difficult to figure out. Of course, since the very nature of the story demands that filming is always at night or in darkness, it makes the addition of costumes with masks all the more difficult to decipher.
If you're a fan of the original, there might be something here for you, but I found it mostly bloody, boring and confusing.