In the early years of the Republic of China, the corrupt Qing government is overthrown by the revolution, and the trend of democratic progress rapidly sweeps across the entire land. However, aside from the chaos of the era, the underdevelopment of the people's wisdom, ignorance, and feudal superstition are still rampant throughout China. The son of the police officer Wang Zhizhang dies due to opium and he disdains the old society for the widespread crime and feudal ideology that poison the people’s minds. Hence, he disguises himself as a Taoist and infiltrates the local businessman Mr. Chen's house to investigate the opium smuggling case.