As he was stuck in traffic on the 405 freeway, Carter received a call from his boss, ordering him to meet with a Hong Kong consul general, who was in town for a diplomatic visit. The consul general's niece, a beautiful and charming woman named Lucy, was in trouble, and the consul general needed Carter's expertise to find her.

Meanwhile, Carter's new partner, Detective Lee (Jackie Chan), had just arrived in Los Angeles from Hong Kong. Lee was an expert in martial arts and detective work, but he struggled to communicate with Carter due to their language barrier.

Carter arrived at the designated meeting spot, only to find that Lucy was being held captive by a group of thieves, led by a slick and cunning crook named Griffin. The thieves had stolen a valuable cache of diamonds, and Lucy was their leverage.

It was a typical Monday morning in Los Angeles, with the city's streets jam-packed with cars, pedestrians, and cyclists. The infamous LAPD detective, James Carter (Chris Tucker), was already having a chaotic day. His partner, Eric Thrale, had just left for a conference in Beijing, and Carter was stuck dealing with the morning rush hour.

As they worked together to unravel the mystery, Carter and Lee encountered a series of hilarious mishaps, cultural misunderstandings, and high-octane action sequences. From a wild car chase through the streets of LA to a showdown with Griffin and his goons, Carter and Lee had to put aside their differences and work together to save Lucy and recover the stolen diamonds.