A team of cops has the mission to protect a witness from being killed. After several killing attempts, the cops will realize how dangerous is the duty they have been assigned to.

Keung and Fai had been good friends since childhood. They both had keen interest in boxing-matches. Having parted with Keung for more than ten years, Fai had become a police officer. On the contrary, Keung had joined an illegal organization as a professional killer. Keung decided to resign from the organization