On July 1, 2043, the crime lord General (Louis Lo) was arrested. A week later, the iron-faced judge Yu Tiexiong (Zhang Weijian) presided over the trial. The General specially sent his underworld henchman Jian (Ekin Cheng) to go back 50 years to find Tiexiong and brainwash him so that he could not conduct the trial. After the government learned of this, the special police officers Iron Face (Andy Lau), Broom Head (Jacky Cheung) and Fat Star (Simon Yam) were specially sent back to 1993 to protect Tiexiong. At that time, Daxiong was a long-term repeater in a middle school in 1993. He was often teased and beaten by his classmate Yu Ji'an (Andy Hui). Only his girlfriend Cai Ni (Charlie Yeung) was sincere to him. The three special police officers of the Flying Dragon sneaked into the school. Broom Head became a teacher, Iron Face became Daxiong's classmate, and Star became Daxiong's follower. They helped Daxiong defeat Ji'an and asked him about Tiexiong's whereabouts, but Daxiong said that there was no such person as Tiexiong in the school. At this time, Jian Yi sneaks into the school disguised as a teacher. On the other hand, Nobita's mother wants to remarry Richard Yu... Can the Flying Dragon Special Police complete the mission in the end?