As a Senior Inspector of the Narcotics Bureau Operation Unit, HEUNG WING (Miu Kiu Wai) profoundly abhors evil. He and WAI SAI-LOK (Raymond Lam) - Senior Inspector of the Intelligence Unit have closely co-operated with each other as peer mentors, frequently solving drug trafficking cases for the Police Force. During an operation to knock down the targets, SAI-LOK discovers clues that HEUNG WING is most likely the corrupt cop in a collusion conspiracy with drug dealers.