It's 1970s era Bay City, California and David Starsky (BEN STILLER) is an uptight cop whose by the books attitude has resulted in him going through twelve partners in just four years. Ken Hutchinson (OWEN WILSON) is a much more laidback cop who's adopted the "if you can't beat 'em, join 'em" philosophy and thus has been committing various crimes under the guise of working undercover.
They couldn't be more different, but police Captain Doby (FRED WILLIAMSON) pairs the two together and they immediately clash, much to the delight of other cops such as Manetti (CHRIS PENN) who can't stand Starsky and his ways.
When the two discover a body that's washed up on the shore, their investigation initially leads them to local wealthy businessman Reese Feldman (VINCE VAUGHN). Little do they know that he and his assistant, Kevin (JASON BATEMAN), have developed a new form of cocaine that's undetectable to drug sniffing dogs or even human taste.
Powerful street informant Huggy Bear (SNOOP DOGG), however, has heard of it and the two cops begin to think Reese is involved. Yet, they can't pin anything on him or his girlfriend, Kitty (JULIETTE LEWIS). Accordingly, they start interviewing witnesses and informants such as the imprisoned Big Earl (WILL FARRELL) and attractive cheerleaders Holly (AMY SMART) and Staci (CARMEN ELECTRA). With their unorthodox ways getting them in trouble with their captain, the two cops try to crack the case.