Watch Knuckledust (2020) HD Full Movie Free on solarmovie.do. Watch Knuckledust (2020) online free. A former marine is trapped in an elite underground fight club. When cops swoop in they discover only...A former marine is trapped in an elite underground fight club. When cops swoop in they discover only one man left alive, him. But all is not as it seems. Is he the sole survivor or a mass murderer?