Cheung Ye-pang is granted an opportunity to study in France with a scholarship. After he returns, he is appointed the first specialist to combat opium sellers in Shanghai. Nurtured by Western culture and values, Cheung is extremely high-spirited and innocent. He takes a series of actions despite having just arrived in Shanghai, without knowing that China, different from Western countries, does not have a sound legal system and social order at the time. Director of the police department Ngai Kwan and the drug lord Paul Tai are sworn brothers. All the illegal trade, including opium selling in Shanghai, is controlled by them. Having bribed Cheung several times but to no avail, they vow to make Cheung’s life a living hell....