In the movie Kickboxer Retaliation, one year after finding vengeance for his murdered brother, Kurt Sloan has vowed never to return to Thailand.
However, while gearing up for a MMA title shot, he finds himself back in Thailand kidnapped and imprisoned there by a powerful gangster (Christopher Lambert). His only shot at freedom is to win an underground death match against a 400lb killer enhanced with state-of-the-art drugs (Game of Thrones’ Hafþór Júlíus Björnsson).
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.