Haisheng (Zhang Jiahui), who has been an undercover agent for eight years, successfully arrests the criminal brother Dark (Wu Zhenyu), thinking that he can finally get rid of the undercover life, Haisheng feels that life is bright again. However, things are not as beautiful as Hai Sheng thought. The award ceremony of reinstatement ended hastily, and his colleagues cast a distrustful look at him instead of concern and appreciation. Police Constable A long (Huang Qiusheng) just comforts him silently. When his undercover girlfriend broke up with him, strangers began to follow him, and Haisheng felt that the life of his police officer was far more painful than that of undercover. He recalled the past between brother Dark and him when he was undercover, and at this time, Haisheng's undercover friend found Haisheng and wanted to escape from his undercover career, which was far from that simple.