The Furian renegade Riddick has another bounty on his head, but when he escapes from his mercenary captors, he's plunged into an epic-scale war waged by the Necromongers. A fascist master race led by Lord Marshal becomes determined to conquer all enemies in their quest for the Underverse and its up to Riddick to stop him from taking over the universe, but things don't go according to his plans and soon mayhem ensues.