香港警察李探长（成龙饰）和美国洛杉矶警探詹姆斯-卡特（克里斯-塔克饰）前往香港度假。卡特原本指望凭着随身携带的一本汉英词典，来好好享受一下这个期盼已久的假期，领略一下这个城市的异国风情。但是一心献身警察的李探长忠于职责，不断地在“折磨”着卡特

他们到达香港后不久，就面对着一宗他们联手以来最大的案子--枚炸弹在美国领事馆爆炸，2位美国海关官员遇难。这2个官员正在着手调查一桩伪钞走私集团案，这个案件涉及制造和贩运数以百万计的制作精良的美元伪钞。

香港警方怀疑这起爆炸案的幕后主使是里基-唐（尊龙饰）--恐怖的伏苍龙帮（Fu-Cang-Long Triad）的那位举止优雅，诡计多端的老大。李探长被指派来侦破这个案子，卡特对此感到尤为恼火，十分不情愿地卷入这个案子的他只能眼睁睁地看着他的度假计划化为泡影。而对于李探长来说，这个案子对他个人来说也是要查清的，里基-唐曾是他父亲在香港警察部队的拍档，他父亲的死亡可能与里基有着直接的原因。

就在香港和美国官员们争夺着这个案子管辖权的时候，李探长和那位十二万分不情愿的卡特开始自己跟踪唐。但是这次卡特探员就象一条离开了水的鱼，李探长终于有机会在他家乡的草地上来给卡特上上课了。诸如：李探长用他并不十分精通的英语对卡特说："在香港我是迈尔克-杰克逊（Michael Jackson），你是图图（Toto）。但是这位快嘴的卡特也有他自己独特的东西来传授给当地人。

李探长和卡特很快就跟踪上了里基-唐和他的手下，试图找到那块印刷伪钞的无价印制版。他俩在香港各地弄出了不少事，包括：在一个卡拉OK歌厅--在那里卡特教那些喽喽们怎么唱那首经典的《Don't Stop till You Get Enough》，在一家“人间天堂”（Heaven on Earth）按摩院，以及在风景如画的维多利亚港（Victoria harbor）内的游艇上举行的一次舞会。

一路上，他们必须与唐的美丽又凶残的女心腹胡莉（章子怡饰），拥有一家价值亿万的旅馆并是里基-唐主要助手的斯蒂文-赖恩（爱伦-金饰），以及那位诱人、神秘，看似腐败的美国特工官员伊莎贝拉-莫利纳（罗塞莉-桑切斯饰）斗智斗勇。

片中的打斗场面从洛杉矶绕了一圈又回到美国国内，一连串的打斗开始于红龙旅馆（Red Dragon Hotel）的夜晚，并在拉斯维加斯（Las Vegas）赌场的赤身裸打而达到了高潮。

Hong Kong Police Inspector Lee (Jackie Chan) and Los Angeles Police Detective James Carter (Chris Tucker) are on vacation in Hong Kong. Carter originally expected to enjoy this long-awaited vacation and appreciate the exotic customs of this city with a Chinese-English dictionary that he carried with him. But Detective Li, who devoted himself wholeheartedly to the police, was loyal to his duty and kept "torturing" Carter

Shortly after they arrived in Hong Kong, they faced the biggest case since they joined forces-a bomb exploded in the US consulate, Two U.S. customs officials were killed. The two officials are investigating a counterfeit smuggling ring that has involved the manufacture and trafficking of millions of well-made counterfeit U.S. dollar bills.

The Hong Kong police suspect that the mastermind behind the bombing is Ricky Tang (played by Zun Long), the terrifying Fu Canglong The elegant and scheming boss of the Fu-Cang-Long Triad. Carter is especially annoyed that Detective Lee has been assigned to solve the case, and reluctantly involved in the case, he can only watch his vacation plans come to naught. For Detective Li, this case is also a matter for him personally. Ricky Tang was his father's partner in the Hong Kong police force, and his father's death may be directly related to Ricky.

When Hong Kong and American officials were vying for the jurisdiction of this case, Detective Li and the 120,000 A willing Carter begins stalking Don himself. But this time Detective Carter is like a fish out of water, and Detective Li finally has the opportunity to come and teach Carter on the grass in his hometown. For example: Detective Li said to Carter in English that he is not very proficient in: "In Hong Kong, I am Michael Jackson (Michael Jackson), and you are Tutu (Toto). But this fast-talking Carter also has his own unique to pass on to the locals.

Inspector Li and Carter soon followed Ricky Tang and his men , trying to find a priceless copy of the counterfeit note. The two have had quite a few things all over Hong Kong, including: At a karaoke bar - where Carter taught the minions how to sing the classic " Don't Stop till You Get Enough," a Heaven on Earth massage parlor, and a dance on a yacht in picturesque Victoria harbour.

< p style="text-indent: 2em; text-align: left;">Along the way, they must meet Tang's beautiful and murderous confidante Huli (Zhang Ziyi), who owns a hotel worth billions and is Ricky's daughter. -Steven Ryan (Ellen King), Don's main assistant, and Isabella Molina (Rosalie Sanchez), a seductive, enigmatic and seemingly corrupt US Secret Service officer Fighting wits and courage.

The fighting scenes in the film circled from Los Angeles and returned to the United States. The night at the Red Dragon Hotel culminated in a naked fight at a Las Vegas casino.