There has always been a dark underground world on Earth. There, two major races - vampires and werewolves - are fighting to the death, and each side aims to eliminate the other race. Once, while chasing several defeated werewolves, Selene (Kate Beckinsale), the "Moon Goddess" of the vampire clan, discovered that the werewolves were plotting to kidnap Michael (Scott Speedman), a human doctor. Knowing that the werewolves must have some intentions, Selene went to the wolf den alone to investigate. Unexpectedly, she was ambushed by the werewolves and was seriously injured, but was fortunately rescued by Michael. On the way Michael sent Selene back to the vampire camp, he was accidentally bitten by a werewolf, which revealed the mystery of Michael's life experience and the werewolf's conspiracy...