- "Like I said, I'm good with calculation."
The Dark Knight
- "Batman has no jurisdiction, he'll find him and make him squeal. And I know the squealers when I see them, and...(points at Lau on the TV)"
- ―The Joker[src]
Lau is the CEO of Lau Security Investments Holdings, a major business in Hong Kong whose success drew the attentions of Wayne Enterprises. During a business meeting, Lau speaks before the board of directors, suggesting a powerful joint business venture between their two companies. Lucius Fox, CEO of Wayne Enterprises, eagerly embraces Lau's proposition, despite Bruce (likely exhausted from his nightly ventures as Batman) being asleep in a chair.
After the meeting, Lucius approaches a now awake Bruce, stating that although Lau's company indicates powerful economic potential at "8% annual growth", the numbers lead Lucius to suspect that much of this is off the books, and probably illegal. Bruce simply accepts this, having suspected that this was the case, and his approach of a business deal was to "get a closer look at their books."
During the Mafia meeting that occurred due to both the Joker's recent bank robbery as well as the closing fist of the Gotham City police force, Lau's true nature is revealed as the man hosts a video conference with Sal Maroni, The Chechen, Gambol and the rest of Gotham's organized crime. Lau, firmly aware that the GCPD's Major Crimes Unit has shut down all other money laundering services in Gotham, has seized the Mafia's savings to prevent it from capture, and has moved it to an undisclosed location to ensure its safety. He also did this without their knowledge beforehand in order to ensure the GCPD could not gain any hint of its location. Lau cites that because of his international status, he is beyond Gotham City law, and cannot be captured or forced to testify.
However, the meeting is interrupted by the Joker, who comes forward to remind them that Batman has no such jurisdictions and will find Lau regardless of his being in Hong Kong. Lau, unnerved by the Joker's accusations of being a squealer, as well as his violently suggestive body language, proceeds to switch off the television, ending his involvement in the meeting.
With Lau gone, Harvey Dent, Jim Gordon, and Batman held a meeting on top of the Gotham City police precinct, where Dent explains that Lau is gone. After some accusations of distrust between Gordon and Dent, the district attorney asks Batman if he could somehow get Lau back.
After meeting with Bruce to discuss the particulars of their plan, Lucius then travels to Hong Kong to directly apologize to Lau for needing to call off the meeting. During this time, Lucius both plants an electronic magnetic pulse (EMP) device (in the form of a cell phone) at the security desk, while at the same time applying his own device to map the building by way of sonar to assist Batman in his mission.
During the night, Batman launches his assault after the EMP device activates, blinding security to the break in. During the battle, Batman captures Lau and uses him as a human shield against the paid cops who come to assist the CEO. With the help of a CIA inflitration tool called sky hook, and a plane used by hired smugglers, Batman manages to successfully lift Lau from Hong Kong, and delivers him to Jim Gordon (both figuratively and literally, as the scene where he is taken in by the police had a sign on him saying "please deliver to Lieutennant Gordon" a'la a mailing package.
While in custody, Lau refuses to turn over the location of the Mafia's funds until Rachel Dawes moves to send him to county prison, which would leave Lau at the mercy of any inside men the Mafia currently have in lock up. Lau quickly makes a counter offer, instead of delivering the money, suggests he would be willing to testify knowledge of all the Mafia's investments, a move which Dent plans to use in a RICO court case to prosecute all members. Lau implies he intends to keep all that money for himself once his clients are behind bars. Under the agreement, Lau would remain safe in the MCU precinct until he is due in court.
Lau's word brings almost all of Gotham's mafia criminals into the court room, until the Joker is hired. The violence that ensues slows the prosecution with the deaths of the presiding judge and police commissioner, as well as the attempts upon Harvey Dent's life.
Lau remains in lock up until the Joker is captured by the combined efforts of Gordon, Dent, Batman and the GCPD. While in custody, the Joker arms a bomb he hid within one of his captured goons and manages to free and escape with Lau. Not long after, Lau is forced to release the whereabouts of the Mafia's savings.
With their money safe, the Chechen meets up with the Joker on a container ship. Lau, tied to the top of a mountain of dollar bills and trapped in a straitjacket, died either from the flames or smoke inhalation as the Joker set the pile of money on fire, after pouring gasoline on the money.
Lau displayed an intelligent but highly arrogant and extravagant personality. He was intent on blackmailing the mob dealers into giving him money and underestimated Batman and the Joker. He was arrogant enough to boast that he was good with calculations, when they only had his word for it. Lau was cowardly and backed away from meeting the other mobs when the Joker intervened.
Behind the scenes
- While the movie itself doesn't specify Lau's fate, the movie screenplay states that Lau is bounded at the pile of money and it also specifies that he screams when the Joker burns the money, meaning that he was, in fact, killed by the fire. In the actual movie, Lau doesn't scream when the money was burned, although he never speaks, likely implying that he was gagged.