From where the underworld (2003) ended, Selena and Michael are escaping from the vampire. As the cause of Victor's death, Selena can only hope to intercede with Marcus, the last remaining old man. However, Marcus has awakened and became a more powerful creature than before. Now his only remaining goal is to awaken his werewolf brother William and free himself from his eternal imprisonment. As time goes by, Selena and Michael must piece together the last clue to uncover the secrets of their bloodlines and stop Marcus before it is too late.