In 2008, Yao Yuan, the captain of the Narcotics Squadron of a city's Public Security Bureau, and his deputy captain Jin Rui were on a mission to arrest someone. Yao Yuan died. The Provincial Public Security Department sent Jin Rui to teach at the Municipal Police Academy. Yao Yuan's newlywed wife Song Errui was Jin Rui's former lover. The five students in Jin Rui's class each had their own strengths. As they spent time with Jin Rui, they gradually grew into reserve police officers with a sense of responsibility and a keen sense of crime. The same moral education philosophy made Errui understand Jin Rui more and more. The organization arranged for Jin Rui to teach at the police academy to make long-term arrangements for a transnational drug-related case; a group of reserve police officers led by Jin Rui and Errui successfully solved the case, and a new generation of tasks began.