The story is a bit convoluted and it's not really clear what is going on, other than the hemophages were a result of something created in a lab that "got out" and many were infected. It shortens the life span, but also makes the infected very strong and fast, a super race, if you will. The humans have rounded up the hemophages over the years and done experiments on them and such, and now Daxus, the evil Vicecardinum and ruler of the humans, wants to wipe out the hemophage population entirely using Six (played by Cameron Bright from Birth and X-Men The Last Stand), a lab-created clone whose body contains the subtance needed to eradicate them. Or does it?
Starscream saw this movie and really didn't like it, saying Milla plays the same generic ass-kicking chick she always plays. I say so what? Milla was born to play these roles and I love her as the ultimate female sci-fi warrior. As Ultraviolet, she is able to change the color of her outfit and hair with the touch of a button, as well as materialize weapons out of thin air the same way. They never really explain how, but I don't really care that they didn't explain it all - its just cool to watch. Hemophages are strong and fast, as I mentioned, so the fight scenes are fantastic to see. Also, they have found a way to control gravity, so a motorcycle chase is not limited to the ground, as Violet can also ride up the sides of buildings. It all feels very Japanese and sci-fi and it's an all-around good time.
Special features include a making-of featurette and commentary by Milla, along with extra scenes in the Unrated version. Mind you, these scenes are integrated into the movie, and while there was only one specific scene that I knew was additional (since it has been quite some time since I saw this flick in the theaters), it was emotional and pivotal. It showed someone from Violet's former life as a human having moved on without her.
While not a true vampire movie in the tranditional sense of the word, if you are in the mood for a sci-fi action flick that is not your run-of-the-mill story, give Ultraviolet a try.