English Title: Line Walker
Cantonese Title: 使徒行者 (si to haang je) “Apostle Walker””
Cast: Michael Miu 苗僑偉，Charmaine Sheh 佘詩曼，Raymond Lam 林峯，Sharon Chan 陳敏之， Benz Hui 許紹雄，Elena Kong 江美儀，Sammy Sum 沈震軒，Oscar Leung 梁烈唯
Airing date: 25 August 2014 (Replacing Black Heart White Soul)
Sequel: Line Walker 2- The Prelude (Prequel) 2017
Following the sudden death of his co-worker and best friend, Chief Inspector of the Criminal Intelligence Bureau (CIB) CHEUK HOI (Michael Mui) discovers that they have lost contact with all five of their undercover officers who have been in connection with the deceased. All five of the undercover officers are in possession of highly confidential information concerning the safety of the central figure of the police force and even the whole of society. Determined to locate the undercover officers’ whereabouts, CHEUK HOI eventually manages to contact one of them, DING SIU-KA (Charmaine Sheh), who is the lady boss of a foot spa. In order to return to her true identity, SIU-KA promises CHEUK HOI to sneak into a gang and deliberately approach SIT KA-KEUNG (Raymond Lam), an active member of an illegal betting syndicate. The two thus develop a seemingly romantic relationship based on lies…… Just when SIU-KA is about to get to the root of the matter, CHEUK HOI suddenly appears to thwart her action. Due to the intervention of an ICAC agent, MOK SIN-YAN (Sharon Chan), CHEUK HOI gets to know her elder sister MOK SIN-CHING (Elena Kong). Meanwhile, gang leader CHUM FOON-HEI (Benz Hui) is released from jail, and his assistant LIN HO-KAN (Sammy Sum) catches the attention of CHEUK HOI because of the way that he deals with things. In addition to the complex identities involving both sides of law, they all claim to be fightingfor justice. So, who will eventually be the one to uphold justice?