In the year 2043, a shadowy crime lord known only as The General schemes to seize global power. After his arrest and sentencing by a judge, his loyal lieutenants—Kent, Thai King, and Toyota—plot a dangerous backtrack to 1993 to kill the Judge before he can take office.
During a clash with The General's minions, the Future Cops Lung, Broomhead, Ti Man, and Sing learn of the threat. The Police Director orders them to travel back to the past to protect the Judge, though Lung stays behind because he is the Director's brother-in-law.
Arriving in 1993, they crash into the life of Tai-Hung, a 28-year-old high school student who welcomes them into his home and family, letting them live among him as they blend in with the local scene. [Ti Man] pretends to be a fellow student and begins a romance with Tai-Hung's sister, Chun-May. [Broomhead] assumes the role of a music teacher at the school and becomes involved with one of the students, while [Sing] shadows Tai-Hung as his servant, protecting him from relentless bullies. At the same time, Tai-Hung himself pursues a romance with his longtime friend, Choi-Nei.
The villains soon close in. [Kent] goes undercover as a teacher to uncover Tai-Hung's true identity, and he delivers a cruel blow by poisoning [Ti Man], regressing his intelligence to a five-year-old, before coaxing Crab Angel to lead him to a lover's spot. [Broomhead] tails the pair, and after a series of confrontations decides not to take Kent's life. In a twist of fate, Kent injects the antidote to restore Ti Man's mind and then slips away.
The General seizes control of the school, appointing himself principal and imposing a lockdown to pressure the cops into surrendering Tai-Hung.
At Tai-Hung's birthday party, he realizes that the villains are targeting him and contemplates avoiding the danger. The situation escalates further when the cops inject microchips into Tai-Hung, Chun-May, and Tai-Hung's parents to grant them super powers.
The climactic showdown unfolds inside the school as the Future Cops confront The General and his forces. A hoverboard crash shakes the building, triggering the awakening of Tai-Hung's powers. While the others engage in battles with The General, Kent defects to join the defenders. Only when all the heroes unite their strengths do they manage to overpower the antagonist and restore the balance. Even Kent, who defected to the defenders, helps turn the tide as the team finally prevails.
