Pai Piao plays a Chinese who comes to Seoul in order to find an old friend. There, he witnesses how the Japanese men under Chen Hung Lieh's orders mistreat the Korean people of a Taekwondo school and also the people of the town.
He decides to help them and when they see that he is more powerful than them, the Japanese decide to ask him to join them. As he accepts the rendezvous with Chen Hung Lieh (but not to join him, he just wants to tell him to stop to bully the villagers and the school of Taekwondo), the students of the Taekwondo believe that he is a traitor and they don't want him as a friend anymore.
Finally, the misunderstanding is cleared up and they all join forces to get rid of the Japanese after these ones killed some students of the school.
That's a superb non stop action movie and Pai Piao is great in this role.