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.