Hong Kong was a corrupt society during the early 1970's. To fight against the corruption situation, Governor Maclehose instructed Sir Blair Kerr to take investigation. Sergeant Wong was called for help. After much effect, Wong gathered enough evidence against Luk's acts. However, they were attacked on their way of sending witness to court. At last, Governor Maclehose approved the establishment of "ICAC". And Wong was assigned to investigate against corruption and take revenge on Luk and his group.