Despite negative psychological evaluations, Mike Wong is assigned as the captain of the SDU, a special task force linked to the Customs Department. Their mission: apprehend nasty drug dealers, led by the “Ice Queen.” To do this, Mike has to team up with customs cop Minnie. Despite their clashes, the two learn to understand each other, but not before things get bad.

Lin is a plain-clothes cop in the crime-riddled district of Mongkok who bungles a vice operation directed at mainland prostitues. He falls for a ditsy hooker who tells him the love of her life is a killer who once svaed her life in a shootout.

After his father abandons the family, Autumn Moon drops out of high school and becomes a debt collector for the Triads. On his rounds, he meets and falls in love with Ping, a daughter of one of the Triads' clients. She is suffering from a fatal kidney disease, and to pay for her medical expenses, Autumn Moon takes an assassination contract, but as he slips deeper into the criminal underworld, he's haunted by a figure from his past.