Kurt Sloane must learn the ancient kick boxing art of Muay Thai in order to avenge his brother.

David's brother, Kurt, defeats Po in Karate Tiger 3 - Der Kickboxer (1989). A year after Po kills Kurt, David, who has a kickboxing gym in LA, is manipulated into a match against Po.

David Sloan travels to Rio for a kick-box exhibition. There he saves two youngsters and stops a white slaver.

David Sloan must travel to Mexico to save his wife from a savage drug lord who's also an old nemesis.

After David Sloan is murdered, it's up to kick-boxing champ Matt Reeves to avenge him.

Eric and Kurt Sloane are the descendants of a well-known Venice, California-based family of martial artists. Kurt has always been in older brother, Eric's shadow, as he lacks the instincts needed to become a champion. Against Kurt's concerns, Eric accepts a paid offer and travels to Thailand to challenge the Muay Thai champion Tong Po and fails with dire consequences. Kurt sets out for revenge. He trains with his brother's mentor, Durand, for a Muay Thai fight against the merciless champion, Tong Po. Durand first thinks Kurt is impossible to train, but through a series of spiritual exercises and tests, Durand discovers that Kurt has a deeper strength that will carry him through his final showdown with Tong Po.

One year after the events of "Kickboxer: Vengeance", Kurt Sloan has vowed never to return to Thailand. However, while gearing up for a MMA title shot, he finds himself sedated and forced back into Thailand, this time in prison. He is there because the ones responsible want him to face a 6'8" 400 lbs. beast named Mongkut and in return for the fight, Kurt will get one million dollars and his freedom back. Kurt at first refuses, in which a bounty is placed on his head as a way to force him to face Mongkut. Kurt soon learns he will have no other choice and will undergo his most rigorous training yet under some unexpected mentors in order to face Mongkut in hopes to regain his freedom. But is later beaten up by mongkut in the the first, but later gears up and defeated mongkut thereby gaining his freedom and pay.