Underworld

Vampires and werewolves are at war in a postmodern-looking world. Kate Beckinsale plays the part of one of the undead, killing werewolves as her duty to the race of vampires. When a hunt goes bad, she goes into hiding, and discovers that the long-thought-dead leader of the werewolves is in fact alive, and manages to fall in love with one of the enemy. It turns out that there's a conspiracy that ranges to the highest levels of the vampire world, and she's caught in the middle.