Underworld is a 2003 action horror film directed by Len Wiseman about the secret history of Vampires and Lycans (an abbreviated form of lycanthrope). It is the first (chronologically, the second) installment in the Underworld series.
The main plot revolves around Selene (Kate Beckinsale), a vampire Death Dealer hunting Lycans. She finds herself attracted to a human, Michael Corvin (Scott Speedman), who is being targeted by the Lycans. After Michael is bitten by a Lycan, Selene must decide whether to do her duty and kill him or go against her clan and save him.