Aging Amos "Scrap Iron" Fletcher has finally made it to Vegas, only to lose his first big-league fight and be falsely accused of selling secrets to his sparring partner's opponent. So he heads back to Trenton and hooks up with TNT, a reckless but kindhearted young boxer who's also down on his luck. With a little help from the spirit of Sonny Liston, Amos trains TNT for a series of high-profile fights and launches a daring gambit to reclaim his own reputation.