For centuries, two races have evolved hidden deeply within human culture – the aristocratic, sophisticated Vampires, and the brutal, feral Lycans (werewolves). To humanity, their existence is no more than a whisper of a myth. But to each other, they are lifelong mortal rivals, sworn to wage a secret war until only one race is left standing.

One night while riding the subway, medical student Michael Corvin is caught in a fierce firefight between the two mysterious “gangs.” He catches the eye of a striking and sophisticated woman, the Vampire warrior Selene.

In her desperation for an ally, Selene awakens the Vampire leader Viktor (Bill Nighy) from his five-hundred-years sleep.

“He's reawakened a century too soon and is not too pleased about that,” comments Bill Nighy.

“He thought they’d cleared up the werewolf trouble hundreds of years ago by killing everybody. But, in fact, that wasn't the case, and now the werewolves have regrouped and are threatening the vampire world.”

When the Lycans attack again, Selene takes on their most skilled fighters but is powerless to stop Michael from being bitten by the ruthless Lycan leader, Lucian (Michael Sheen).

The blue contacts that Bill Nighy wears throughout the film left him virtually blind.

Kate Beckinsale met her future husband, director Len Wiseman, on the set of Underworld.

Co-writer Kevin Grevioux wanted to create a type of Romeo & Juliet story, but instead of Montagues and Capulets, it would be werewolves and vampires.

Speedman underwent arduous hours of prosthetic makeup application. His transformation from human to werewolf took five hours to complete, and it took a seven man team an hour to remove.

Selene believes that Lucian is organizing a werewolf army intent on revenge after years of persecution at the hands of the arrogant Vampires.

This film marks Len Wiseman’s feature film directorial debut after working many years in the art department of blockbuster hits such as Godzilla, Men in Black and Independence Day.