A vampire and werewolf on the run try to solve the origin of their species while trying to evade vampires that want them killed. Selene, who is considered a traitor by her vampire clan, is on the run with Michael, a werewolf/vampire hybrid descended from the bloodline of Corvinus, the original immortal. They are being hunted by Kraven, a vampire officer, and Selene must awaken the vampire original Marcus (who is the son of Corvinus, and the brother of William, the original werewolf) to tell him that the vampires have been compromised.
She and Michael hideout and she instructs Michael to stay behind while she plans to go to the vampire lair to complete her mission. Once there, she learns that Kraven has already awakened Marcus, who is now a flying monster. Marcus kills Kraven and upon drinking his blood, he absorbs his memories. Meanwhile, Michael has disobeyed Selene's orders and has gone out of the safe house to eat. He runs into police, and attracts unwanted attention. On the streets, Michael and Selene meet up, and commandeer a vehicle, Marcus is flying above. They are able to escape and hide in a warehouse.
Selene figures out that Marcus must be after her necklace, for reasons she doesn't quite know yet. They seek out Tannis, a man who might know the answers. At his house, they are attacked by werewolves, when they reach him, he tells them quite a story. That her necklace is one of two keys that can open William's prison. Selene now realizes that Marcus wants to free his werewolf brother. They leave to meet another contact that Tannis directs them to. Marcus then arrives and kills Tannis, from his blood, he learns that Selene was just there to see him and finds out Selene's next move.
Selene and Michael meet with Corvinus, who's in possession of the other key. However, Marcus also arrives and a fight ensues. Marcus kills Michael. Marcus then kills his father Corvinus, but not before Corvinus feeds his own blood to Selene to give her extra power. Selene leaves the ship, which explodes, destroying everything.
Selene goes to William's prison, and fights more werewolves there which have turned from William's bite. William is now free, but Michael comes back to life and fights him. Selene fights Marcus and shoves him in the chopper blades. Michael decapitates William. We discover the extent of Michael's abilities, while Selene has absorbed some of Corvinus' power which allows her to walk in sunlight.
Best scene in story:
The climactic fight scene, Selene stabbing Marcus and shredding him, while Michael rips William's jaw off.
Opinion about the main character:
Selene wants to right the wrongs of the vampires, only to discover that the one she seeks to help her is also her enemy.