Forced to leave service after he was afflicted with blindness, a former detective ekes out his living by solving cold cases for police rewards. When an attractive, young hit-team inspector enlists his help in a personal case, he decides to take a stab at it with his own personal agenda.

Master director Johnnie To's first collaboration with superstars Sammi Cheng and Andy Lau is a deliciously madcap riff on the "buddy cop" genre, as a retired sleuth with an uncanny ability teams with a quick-witted inspector to fight Hong Kong's criminal underworld, one costume at a time.