Galactic criminal Riddick is on the run, with bounty hunters on his tail. He receives guidance from Aereon , ambassador from the Elemental race, who informs him that a warrior army known as the Necromongers is annihilating all human life in the galaxy in a bid for universal dominance. The wise Aereon urges Riddick into battle, believing he is the one man who can defeat the Necromongers and their leader, the evil Lord Marshal