خلاصه داستان : داستانی بین یک خال در اداره پلیس و یک پلیس مخفی. اهداف آنها یکسان است: پیدا کردن خال و پلیس کیست.

Chan Wing Yan, a young police officer, has been sent undercover as a mole in the local mafia. Lau Kin Ming, a young mafia member, infiltrates the police force. Years later, their older counterparts, Chen Wing Yan and Inspector Lau Kin Ming, respectively, race against time to expose the mole within their midst.