Kickboxing champion Matt Reeves witnesses the murder of his friend Johnny. While investigating the crime, he learns that a Mr. Negaal in South Africa has founded a new kickboxing association and does not leave international champions much of a chance. Johnny had to pay with his life when he did not want to join. Neegal seems to kill everybody who is in his way especially David Sloan from the previous Kickboxer films. Matt is on his own now, but suddenly finds an unexpected ally.

Race-car driver Blaine Striker grows concerned about his younger brother, a student at a medical school on the Caribbean island of St. Heron. General Turner has led a violent coup on this island and may be planning to blow up the school in order to blame the destruction on counterrevolutionaries. Striker infiltrates St. Heron, is captured, stripped to his tighty-whiteys, and electrotortured. He escapes, joins forces with the counterrevolutionaries, and foils a plot to assemble Russian missiles on the island.