L.A.P.D. Detective James Carter is taking a break in Hong Kong to visit his close friend, Chief Inspector Lee from the Hong Kong Police Force. Initially, Carter is eager to indulge in some leisure time; however, his plans are interrupted when a devastating bomb explodes at the American Consulate shortly after his arrival. Inspector Lee is tasked with the investigation, which becomes deeply personal as it emerges that the incident is linked to Ricky Tan (played by John Lone), who was once his late father’s partner and is now a notorious Triad leader suspected of involvement in his father's death.
Tensions escalate as the United States Secret Service, led by Agent Sterling (Harris Yulin), and the Hong Kong Police engage in a jurisdictional dispute over the case. Convinced that Tan orchestrates the operation, Lee learns of a gathering that Tan will attend on his lavish yacht. During this gathering, conflict erupts when Tan is shot by his own associate Hu Li (Zhang Ziyi) amid chaos, leading Sterling to blame Lee for being unable to protect Tan. Subsequently, Carter receives orders to return to Los Angeles, but he and Lee decide to head back together, determined to get to the bottom of the case.
While flying, Carter shares with Lee his theory that every major criminal enterprise has a wealthy white man pulling the strings, identifying Steven Reign (Alan King), a hotel billionaire in Los Angeles, as a suspect. They stake out the Reign Towers where they encounter a captivating Secret Service agent, Isabella Molina (Roselyn Sánchez), who reveals her undercover assignment to expose Reign’s $100 million money laundering operation involving high-grade counterfeit bills.
Their investigation leads them to Kenny (Don Cheadle), an ex-convict known to Carter, who runs an underground gambling den. Kenny informs them about a customer who recently walked in with a suspiciously large sum of cash wrapped in hundred-dollar bills. These bills turn out to be Reign's counterfeits, which leads the duo to a bank affiliated with the Triads. Unfortunately, they are apprehended by Triad goons and knocked out.
After regaining consciousness in Las Vegas, they manage to escape from the Triads and discover that Reign is using a casino called the Red Dragon to launder his illicit funds. At the casino, Lee and Carter split up; Lee attempts to infiltrate the back areas to retrieve the engraving plates used for the counterfeit money while Carter draws attention to himself as a diversion. However, the cunning Hu Li captures Lee, placing a bomb in his mouth before taking him to a penthouse where it's revealed that Tan faked his death and orchestrates the operation.
As Tan and Molina clash, Carter bravely frees Lee from the explosive device just in time, sparking an intense confrontation with Hu Li. Meanwhile, Reign, realizing he might lose everything, decides to cut ties with Tan, leading to his demise at Tan's hands. With an ultimate showdown brewing, Lee confronts Tan, who confesses to murdering Lee's father. In the end, Lee kicks Tan out of a window, ensuring he meets a fatal fall.
With Hu Li still a threat, she detonates a time bomb, but Lee and Carter narrowly escape by leaping from the exploding penthouse, sliding down decoration wires to safety on the street below. Later, at the airport, Sterling expresses gratitude to Lee for his invaluable assistance, and Molina steals a moment to kiss Lee, which Carter observes with a mixture of amusement and surprise. As they prepare to part ways, Lee reveals his dream of attending a New York Knicks game at Madison Square Garden. Carter seizes the opportunity to suggest one more vacation together, leading them to plan an adventure in the Big Apple.
