New York Police Lieutenant James Dempsey kills his corrupt partner Joey and has to lay low until the case can be further investigated. His superior O'Grady sends Dempsey to London, England as part of an exchange of officers. Chief Superintendent Spikings, head of SI 10, is not to pleased to have a 'yank' forced onto his department. He decides to couple Dempsey with his complete opposite, Sergeant Makepeace, an upper class English rose on a case involving a mysterious shipment of caviar.
Frank Price is sprung out of jail, only to be killed by his accomplices. Spikings suspects Price's boss Jack Lang, but when Lang's granddaughter Debbie is kidnapped it seems like someone else is trying to instigate a gang war. Meanwhile, Dempsey is more interested in wooing fellow American Angie Hughes.
Dempsey takes the place of American hit-man Schwartz to infiltrate a gang of drug dealers who are lacing T-shirts with heroin. Little does he suspect that their main contact, Lei Shan carries a grudge against the real Schwartz. When Makepeace gets her hands on one of the T-shirts via one of her contacts, the undercover Dempsey finds himself forced to bump her off.
Makepeace poses as reporter Debby Smith to get close to hoodlum 'Marocco' Jack and ends up saving his life from a rival gang. Dempsey joins Marocco's gang by posing as an American driver called Andy Sallapuccio, whom they need to pull off two simultaneous jewel heists. Meanwhile Spikings is facing complaints from upstairs that might lead to SI 10 being shut down.
After a long night on a fruitless stakeout, an SI 10 colleague is shot by an American hit man right in front of Dempsey and Makepeace. The hunt is on for the killer, who's been targeting a pimp but whose real target seems to be somebody higher up. As luck would have it, one of the prostitutes happens to be an old school chum of Makepeace.
Interview with Michael Brandon and Glynis Barber, recorded in January 2006 at Pinewood Studios