Star Chow is about to be kicked out of the Royal Hong Kong Police's elite Special Duties Unit. But a senior officer decides to give him one last chance: Star must go undercover as a student at the Edinburgh High School in Hong Kong to recover the senior officer's missing revolver. A SWAT team leader is forced by his captain to go undercover as a high school student to retrieve the captain's personal gun which was stolen during a school field trip to the police station.