 The drama centers around a squad of undercover officers from the Criminal Intelligence Bureau (CIB) of the Hong Kong Police Force, who are closely following the activities of Yee Fung (義豐), a large triad society.Damian Lau portrays Harry Kung / Kung Kar-pui (鞏家培), the senior superintendent of CIB.Fala Chen portrays Jodie Chau / Chau Mong-ching (周望晴), known as Madam Jo, the senior inspector of CIB's A team.