這是一個發生於抽離世界的殺手故事︰曾被尊稱「閻王」的閻武，闖禍導致家散人亡，淪為低端殺手，造就神級殺手「Zero」喬星崛起，殊不知二人曾各自因台灣富商柯正雄而改寫了命運……閻武幸有知己鳳姐姚淑嫻，成為他與女兒閻素之的聯繫橋樑，卻不幸被行事乖張的女殺手易蘭纏着，叫苦連天。喬星開設咖啡室作掩飾，聘請了單親媽媽錢向茜，並心儀身分撲朔迷離的廟祝林森森。「殺手獵人」出現，迫使閻武與喬星來個生死對決……
喬星（陳豪飾）、閻武（黎耀祥飾），一個是如日中天的神級殺手，一個是風光不再的潦倒殺手。兩人卻有著共同的敵人，聯手復仇令他們結下不解之緣。 “殺手獵人”的出現卻威脅著整個殺手界。殺手、清道伕、經理人悉數出手拆解危局。殺手界外的單親媽媽向茜（李佳芯飾）、一樓一鳳姐淑嫻（江美儀飾），也因與喬星、閻武的感情被捲入危機……喬星為解決殺手獵人，竟導致閻武之女重傷昏迷。閻武為向女兒交代，必須殺喬星；喬星為了向茜，必須活下去。兩代殺手之王，最終走向了沒有退路的對決……
This story about assassins takes place in a fanciful world. Yim Mo, who used to have a prestigious nickname “Yama”, has caused his family to break up with fatal consequences due to his blunder. He ends up as a mediocre killer. He has facilitated the emergence of a formidable hitman called Kiu Sing, aka “Zero”. However, the duo’s destinies are rewritten because of a Taiwanese tycoon called Or Ching-hung. Yim Mo counts himself lucky as his buddy Yiu Suk-han, who is a hooker by profession, manages to bridge the communication gap between him and his daughter Yim So-chi. Unfortunately, Yim Mo’s life has become very difficult as an eccentric female assassin called Yik Lan keeps clinging to him. Kiu Sing opens a cafe as a decoy and hires a single mother called Chin Heung-sin. He also has a crush on Lam Sum-sum, who is a temple keeper with a mysterious background. Yim Mo and Kiu Sing are forced to engage each other in a duel as Assassin Hunter shows up.
