Senior Inspector Don Lee (Nick Cheung) relies heavily on the information provided by stool pigeons in his job. Barbarian (Lu Yi) is a painstakingly meticulous arms dealer. Lee needs an informant to infiltrate his gang and recruits street-racer, Guy (Nicholas Tse). Guy delivers, but Lee is unable to effectively act on the information until the final moment. Since Barbarian has not left any evidence, Lee is pressured to convince Guy to become a witness for the prosecution and promises him a new identity in another country. When Guy’s life is put in harm’s way, a disillusioned Lee is left wondering if his quest for justice is worth the price that often has to be paid.