Zhou Xingxing (Stephen Chow) is the captain of the Flying Tigers. He is ordered to go undercover to Sheng Yuqiang Middle School to find the police sergeant's gun stolen during a visit. Zhou Xingxing accepted the mission despite all his helplessness. He quickly adapted to school life. With his strong kung fu skills, he was also supported by many students in the school. Zhou Xingxing also took advantage of the opportunity to investigate the case of missing guns. Another undercover officer in the police force, Cao Dahua (Wu Mengda), also participated in the case and finally joined forces with his classmates to help Zhou Xingxing crack a large-scale arms trafficking case.