Underworld

Perched on the ledge of a building in a rainy night, two black-garbed vampires known as "Death Dealers" track a pair of werewolves who are walking on the street below in their human form. The vampires, Selene and Rigel, specialize in assassinating an ancient species of werewolves known as Lycans. Selene's motivation goes beyond duty; she also wants revenge, for she believes that Lycans slaughtered her family when she was a child. The vampires believe that they defeated the werewolves many centuries ago and killed their leader, Lucian, and that they must now kill off the survivors. As the vampires follow the Lycans into a subway station, the werewolves open fire with submachine guns. In the chaotic shootout, Selene realizes that the Lycans may have been following a human, Michael Corvin, which would be very unusual behavior. After the Lycans retreat from Selene's barrage of machine pistol fire, she tracks them to their lair, where she hears loud howling and finds out that the Lycans have developed a new high-tech bullet to kill the vampires.

When Selene arrives at the vampire coven's ornate, gated mansion, she recounts the evening's events, and urges an attack on the Lycans, but the vampire regent Kraven tells her to drop the matter. Selene secretly continues her investigation, to find out why the Lycans were chasing a human. Meanwhile, in an underground Lycan lair, a scientist named Singe is testing blood from kidnapped descendants of the Corvinus family, to try to find a pure source of the ancient and powerful Corvinus blood type. Soon after Selene finds Michael, the pair are attacked by werewolves, including Lucian, the original Lycan leader, who still lives. After Lucian bites Michael on the shoulder, Selene helps Michael escape, and the two become romantically attracted to each other.

Meanwhile, Selene finds out that when Lucian was supposedly killed, Kraven was the only witness. Sensing a conspiracy between Kraven and Lucian, she wakes a powerful elder vampire, Viktor, who has been in hibernation. But Viktor chooses to believe Kraven and orders Selene to acquiesce to the vampire hierarchy. Meanwhile, Kraven has already planned to kill Amelia (an elder vampire ally) and her group along with Lucian's help. Selene then escapes from the mansion to help Michael.

Selene tells Michael about the feud and her past. After Lycans attack Selene and Michael, Selene captures Singe, a lycan scientist; while Michael is captured by Lycans. Selene brings back the wounded Singe, who admits to Viktor that the Lycans have been trying to combine the bloodlines of the two species with the Corvinus Strain to create a powerful hybrid. After Kraven flees the mansion (because Singe reveals that Kraven and Lucian are working together), news arrives that Amelia, who was coming to awaken Marcus, has been killed by Lycans. Viktor kills Singe and instructs Selene to kill Michael.