红姐（冯宝宝饰）是受人爱戴的鸨母，为人四海豪迈，生平唯一的遗憾是她的女儿小玲（周慧敏饰）－电视红星方小玲因歧视其母而不愿和她相认，但讽刺的是－小玲为巩固自己的地位，不惜向有关人士出卖肉体。后在一次火灾中，红姐为救女儿身受重伤，生命垂危。红姐有一义女叫华女（刘嘉玲饰），在夜总会当小姐，因故与经理起冲突遂愤而辞职，赋闲其间在红姐处养伤，对小玲势利的态度甚为不满，二人势同水火。红姐在拉客时遇见阿玉（罗美薇饰），阿玉为完成到国外念书的心愿而接客，红姐劝其回头，但其心意已坚无法说服。绮华（陈宝莲饰）与医生男友阿海（李子雄饰）是青梅竹马，绮华为阿海下海当小姐，而阿海却与另一女医生发生感情，绮华伤心至极……

ICAC principal investigator William Luk takes his job seriously, and he needs every last scintilla of support from his team to take on the powerful and cunning Supt Wong, who is corrupt to the core. Wong is an enthusiastic tool of the monstrous Malcolm Wu, a cowboy big-time share trader who will stop at nothing to secure a large slice of the upcoming float of the HK government pension fund, worth billions.

廉政公署收到报案人廖雨萍（周秀娜饰）的实名举报，举报正在坐牢的富二代曹元元（林峯饰）涉嫌行贿监狱里的监督沈济全（谭耀文饰）以及惩教员，首席调查主任陆志廉（古天乐饰）决定深入虎穴，卧底狱中。在监狱里，被陆志廉送入监狱的前警司黄文彬（林家栋饰）以及曹元元两大帮派势成水火，陆志廉趁机接近曹元元取得信任。同时监狱外的廉政公署总调查主任程德明（郑嘉颖饰）、国内反贪局行动处处长洪亮（丁海峰饰）也陆港联手，通力合作，最终成功破获贪腐行贿大案。

ICAC Investigator William Luk and JFIU Chief Inspector Lau Po-keung both hit a dead end in their investigation of a bribery case and a money laundering case. In the meantime, William Luk was suspended when model Eva Ng went to Inspector Kenny Ching of ICAC’s Internal Investigation Group L, to file a report against him for accepting a $12M bribe. Lau discovered Luk was set up and whoever framed Luk was connected to his case. He began to suspect the bank manager Thomson Yau was assisting a gangster, Wong Hoi-wo in money laundering activities. When Director Hong Liang of China’s Anti-Corruption & Bribery Bureau (ACBB) provided Lau with important intelligence, it became clear the money laundering activities were connected to a corrupted Vice-Ministerial Level cadre. To clear his name, William Luk put everything on the line…