Redbelt is action-drama movie. The idealistic instructor of jujitsu, Mike Terry, refuses to compete in the ring for principle and is training the promising fighter and police officer Joe Collins. When the stressed lawyer Laura Black stumbles in his academy in a rainy night, she accidentally shots Joe's pistol breaking the front window.
Mike and Joe do not report the incident, and Mike's wife Sondra tells him that they do not have money to repair the window. Mike seeks Sondra's brother in a bar to raise a loan, but he does not find his brother-in-law; he befriends the actor Chet Frank after rescuing him in a fight in the bar.
Chet invites Terry and Sondra for a dinner party at his home and gives a golden watch as a gift. Mike gives the watch to Joe for pawning, but the watch is stolen and Joe gets in trouble in the police. Meanwhile Mike's idea of fight with handicap is stolen by a group of gamblers and Sondra raises a debt of US$ 30,000.00 for an unsuccessful business with Chet's wife. Without other option, Mike decides to fight in the ring to raise the necessary money to pay his debts.