Illegal car racing has become more and more frequent. The police pay special attention to that. Sir Choi suspects that Yiu Wai Sang, the boss of a motor car company, is the de facto director of the races. He sends Siu Fei Hop to get close to him in order to investigate the case.

As Siu Fei Hop is a skilful driver, he wins the champion in an illegal car race. Thus, Wai Sang admires his skill and invites him to join his racing team.

There is a skilled worker called Joe in Wai Sang's company and his driving skill is also outstanding. Wai Sang always urges him to participate in--car races. However, Joe is a man of integrity and he refuses to help Wai Sang.

Joe's girl friend Tina makes Joe shoulder a large sum of medical fees out of her vanity. Siu Fei Hop lends him a helping hand and they become good friends. Siu Fei Hop suspects that Wai Sang smuggles parts of motor car. Thus, he sets a plot to catch him……