Plot
On the last day of British rule of Hong Kong on June 30, 1997, Detective Inspector Lee of the Royal Hong Kong Police Force leads a raid at the wharf, hoping to arrest the unidentified, anonymous crime lord Juntao. He finds only Sang, Juntao's right-hand man, who escapes in a boat. Lee recovers numerous Chinese cultural treasures stolen by Juntao, which he presents as a farewell victory gift to his departing superiors, Chinese consul Solon Han and British police commander Thomas Griffin.
Two months later after Han takes up his new diplomatic post in Los Angeles, Han's daughter Soo Yung is kidnapped by Sang while on her way to school. Han calls Lee to assist in the case, but the FBI, fearing that Lee's involvement could cause an international incident, palms him off on the LAPD. Detective James Carter, an LAPD officer who is disliked by the rest of his precinct for his self-aggrandizing attitude, is tricked into "babysitting" Lee as punishment for botching a sting operation under the guise of an arms deal. Carter has long fantasized about joining the FBI and believes he has been selected for an important case. However, after finding out he has been deceived, Carter decides to solve the kidnapping himself. Carter takes Lee on a sightseeing tour, keeping him away from the embassy while contacting informants about the kidnapping. Lee gets into trouble at a bar when Carter tells him to follow his lead, resulting in Lee calling a black bartender the N-word, unaware it is offensive. Black patrons attack Lee as a result, forcing him to defeat them. Carter tries to prevent Lee from leaving him but Lee makes his own way to the Chinese Consulate, where Han and the FBI await news about his daughter. While arguing with Special Agent in Charge Warren Russ, Carter unwittingly negotiates with Sang, arranging a $50 million ransom drop.
The FBI traces the call to a warehouse, where agents are killed by plastic explosive. Spotting Sang nearby, Lee and Carter give chase but he escapes, dropping the detonator. Carter's colleague and past romantic partner, LAPD bomb expert Tania Johnson, traces it to Clive Cobb, the man arrested by Carter in the earlier botched sting operation. Lee presses Clive into revealing his business relationship with Juntao, whom he met at the Foo Chow restaurant in Chinatown. Clive is initially unwilling to speak but Lee shows him a picture of Soo Yung, causing him to relent. Carter goes to the restaurant alone and sees a surveillance video of Juntao, who is actually Griffin, present as Soo Yung is carried into a van. Lee arrives and saves Carter from Juntao's syndicate, but they are taken off the case as the FBI blames them for the botched ransom drop, with Lee sent back to Hong Kong. However, Carter refuses to give up and appeals to Johnson for assistance to sneak on board Lee's plane, where he persuades him to help stop Juntao together and tells Lee why he never worked with a partner; his father was killed in a routine traffic stop and his partner did not show up. Thinking his father died for nothing, Carter chose to be a cop to honor him.
Griffin later involves himself in the case, revealing more about the HKPF's past with Juntao's syndicate, and implores Han to pay the ransom to avoid further bloodshed. At the opening of a Chinese art exhibition at the Los Angeles Convention Center, overseen by Han and Griffin, the now $70 million ransom is delivered, and Carter, Lee, and Johnson enter disguised as guests. Carter orders the guests to evacuate for safety, angering the FBI, but Lee catches Griffin accepting a remote for the detonator from Sang. Lee and Johnson realize Griffin is Juntao when Carter recognizes him from the Chinatown surveillance tape. Griffin threatens to detonate a bomb vest attached to Soo Yung and demands that the ransom be paid in full, as compensation for the priceless Chinese artifacts which Lee recovered in his raid. Juntao's men start a shootout with the FBI while Carter sneaks out, locates Soo Yung in the van, and drives it into the building within range of Griffin, preventing him from setting off the vest.
Johnson gets the vest off Soo Yung, while Griffin heads to the roof with the bag of money. Lee takes the vest and pursues Griffin. Sang tries to deceive Carter and pulls a gun on him, but Carter shoots Sang first and saves Russ. Lee has a brief altercation with Griffin that culminates in both dangling from the rafters. Griffin, holding on to the vest, falls to his death when its straps are torn, but when Lee falls, Carter catches him with a large flag. Han and Soo Yung are reunited, and Han sends Carter and Lee on vacation to Hong Kong as a reward. Before Carter leaves, agents Russ and Whitney offer him a position in the FBI, which he mockingly refuses, proudly stating he is LAPD.