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.

Chow Sing-Sing returns, only this time he doesn’t go back to school. Instead, Chow goes undercover as the husband of a wealthy socialite, which doesn’t sit well with his fiancée, who tries to convince Chow to quit working as undercover.

Star Chow, an officer in the elite police unit, resigns when he is made a scapegoat for a botched investigation. He goes undercover at a school to complete the case and realizes a bumbling detective is also undercover as a student.

Teddy Walker is a successful salesman whose life takes an unexpected turn when he accidentally blows up his place of employment. Forced to attend night school to get his GED, Teddy soon finds himself dealing with a group of misfit students, his former high school nemesis and a feisty teacher who doesn't think he's too bright.