Independent Commission Against Corruption (ICAC) investigator William Luk and Joint Financial Intelligence Unit (JFIU) officer Lau Po-keung are respectively investigating a corruption and money laundering case, but are unable to find any clues. At this time, Ching Tak-ming of ICAC's L Team (Internal Disciplinary Investigation Team) receives a report from Eva Ng, claiming Luk has accepted a bribe of HK$12 million. Unable to provide an explanation, Luk was immediately suspended from his duties. Lau discovers that Luk was framed which is inextricably linked to the money laundering case he has been investigating. At the same time, Lau also suspects bank director Yau Chi-san assisting the mastermind of a criminal organization, Wong Hoi-wo, in money laundering. Chinese Anti-Corruption Bureau Director Hong Liang arrives in Hong Kong to provide important intel for Lau, revealing that mainland Chinese corrupt officials are involved in the money laundering case. Luk risks his safety to collect evidence to prove his innocence but was imprisoned.