Bumbling private detective Chan Tam is enlisted by police pal Fung Chak to help in the investigation of a serial murder case. The victims a middle-aged man killed at home, a dead woman found in the trash dump, and a teenage girl slain in the park were all killed in grisly manners, but they didn't seem related to one another. With no clue to follow up on, Tam is decidedly at his wits' end.

A school is trying to sabotage a student group's efforts to put on a musical dance number, citing their atrocious grades. The group's leaders must lead everyone to the promised land of academic competency via some innovative cheating methods.

Rookie Sergeant Lee is injured in a shoot-out and is assigned to the dubious-sounding Miscellaneous Affairs Department (MAD). There, he is paired up with Inspector Wong, a jaded and alcoholic veteran who explains that MAD’s role is to answer supernatural calls. Wong explains MAD’s rule number one - there are no ghosts. For every seemingly inexplicable phenomenon, there is a corresponding scientific and rational explanation.