Evolution (Underworld, Book 3)

For more than six hundred years, Selene was a Death Dealer, a vampire warrior dedicated to the destruction of her people's savage enemies: the werewolves. For all of his mortal life, Michael was an ordinary human -- until he found himself caught in the middle of a shadow war between immortal rivals. Bitten by both a lycan and a vampire, he has now become a hybrid creature whose ultimate potential remains unknown. Together, Selene and Michael have become outcasts -- and targets, for a long-buried menace has risen from the depths of history in search of unholy vengeance.