Under Yu Zui's instigation, Zheng Chao betrays Fu Guosheng and established his own drug ring; causing him to be estranged from his former boss. Zheng Chao was later caught, and Yu Zui replaces Zheng Chao as the leader of the criminal organization. His rise to position raises Fu Guosheng's suspicion, who sends Si Hai to test him. Yu Zui discovers Fu Guosheng's plan in time, and gradually gains the latter's trust. Lin Jingyu also joins Yu Zui in his undercover mission and together the two of them tries to crack down on Fu Guosheng's crimes. At the end of the season, Fu Guosheng was arrested with the help of an unexpected person and Yu Zui rejoins his team mates at the Police Academy. However, he realizes that An Jialu is at the hands of Fu Guosheng's subordinates. Together, the team sets out to rescue An Jialu.
It is based on the crime novel of the same name by Chang Shuxin.