Chan, an articulate senior detective nearing the end of his career, is taking care of the daughter of a witness killed by ruthless crime lord Po. Martial arts expert Ma is set to take over as head of the crime unit, replacing Chan who wants an early retirement.

Cantonese pop star Ronald Cheng stars as spoiled rich kid Dragon Lung, who spends his days idly loafing with his fellow teenaged trust-fund brats, Sue-hei (Sam Lee) and Gold (Tat-ming Cheung). When the trio's frustrated fathers force their sons to attend a police academy for some much-needed discipline (or else face the loss of their hefty inheritances), the would-be cadets bungle their way through boot camp in a series of madcap, gun-fueled hijinx.