An ailing veteran cop whose relentless determination to do away with an untouchable gangster has led him to employ a series of unethical tactics finds his investigation complicated by the arrival of principled new inspector and the death of a fellow cop in this explosive underworld tale from Skyline Cruisers director Wilson Yip. Facing an inevitable retirement, the beleaguered and cancer-stricken Detective Chan (Simon Yam) has grown desperate to put away Teflon-coated crime boss Po (Sammo Hung) -- so desperate that he even begins planting false evidence and tampering with video in hopes of making a charge against Po stick. As Detective Chan begins to grow accustomed to thoughts of retiring and make way for honest incoming Inspector Ma (Donnie Yen), the ongoing investigation hits a snag when an undercover cop who has infiltrated Po's gang is mysteriously killed. ~ Jason Buchanan, Rovi