In this Hong Kong thriller inspired by actual events, Kin (Anthony Wong Chau-Sang) finds his life in a downward spiral after a careless cabbie mows down his wife and unborn child. Out for revenge, he embarks on a killing spree to rid the city of reckless taxi drivers. But the heat is hot on his trail when Kin's best friend, unsuspecting police officer Yu Kai-Chung (Rongguang Yu), is tasked with finding the man responsible for the murders.