A war has been raging between the Vampires and Lycan for centuries, Selene (Beckinsale) is a death dealer, assigned to hunt down and eradicate the last of the Lycan. When she comes across Michael Corvin(Speedman)who holds the key to end the war she must decide where her alligances will lie.

A war going on for centuries between vampires and Lycans/werewolves, never seen by humans eyes, until one of the werewolves by the name of Lucian (Michael Sheen) finds out about one human that can bond with vampire blood and Lycans blood, Michael (Scott Speedman). Selene (Kate Beckinsale) is the vampire Death dealer that finds out why the Lycans are following Micheal and falls in love with him. Kraven (Shane Brolly) is the leader of the vampire house after Viktor (Bill Nighy) dies and wants Selene by his side, but she is a wild cat to break.

This movie continues the saga of war between the Death Dealers (vampires) and the Lycans (werewolves). The film traces the beginnings of the ancient feud between the two tribes as Selene (Kate Beckinsale) and Michael (Scott Speedman), the lycan hybrid, try to discover the secrets of their bloodlines. All of this takes them into the battle to end all wars as the immortals must finally face their retribution.

Beginning where Underworld finished, Selene and Michael are on the run from the vampires. Being the cause of Viktor's death, Selene can only hope to plea to the last remaining elder, Marcus. However, Marcus has already awakened and has become a more powerful creature than before. Now his only remaining goal is to awaken his Lycan brother, William from his eternal imprisonment. With time running out, Selene and Michael must piece together the final clues to unlock the secrets of their bloodlines and stop Marcus before it's too late.