The film stars an international cast of martial arts film actors, including Angela Mao, Jhoon Rhee (the father of American Taekwondo), Anne Winton, Wong In Sik (Ing-Sik Whang), Carter Wong, Kenji Kazama, Sammo Hung, Biao Yuen, and Golden Harvest producer Andre Morgan.

This leads to an explosive climax with the heroes having to fight the likes of Wong In Sik (Hwang In-Shik), Sammo Hung and Kenji Kazama.

Rhee landed the role in the film with help from his friend Bruce Lee whom he met in 1964 while both were performing demonstrations at an international karate event held in Long Beach, California.

[3] In 1972, Lee went to Golden Harvest Films boss Raymond Chow with the idea of making a movie about Taekwondo with Rhee in lead role.

[6] An article in the Lowell Sun suggested that Winton's role, with her as a blonde American girl in the film along with some other new approaches may have also been for international appeal and profit.