After killing the policeman who arrested him, drug dealer Zhang Hu flees. Three years later, Zhang Hu's drug gang finds the illegal-truck driver Li Jun and forces him to transport goods for them. Anti-drug captain Tang Xudong succeeds in convincing Li Jun to be an informant with pay as Li Jun needs the money for his wife’s medical treatment, and thus begins his informant operation laden with danger. As things develop far beyond Tang's plan, it turns out that Li Jun has a bigger purpose.