FBI agents Marcus Anthony II and Kevin Copeland ruin a drug bust accidentally. Their boss offers them a reprieve if they escort sisters Brittany and Tiffany Wilson safely to a weekend-long fashion event in the Hamptons. The Wilsons are the rich, shallow socialite daughters of Wilson Cruiseliners CEO Andrew Wilson, whom the police suspect will become the next victims in a string of high-profile kidnappings.
On the drive, the sisters' dog leaps out of the car window, causing Kevin to lose control. The sisters suffer minor facial cuts. With the sisters refusing to be seen with cut faces, Kevin sends them into hiding; he has a makeup expert friend create prosthetic disguises so he and Marcus can replace them.
Kevin as Brittany and Marcus as Tiffany meet the sisters' three best friends – Lisa Anderson, Karen Googlestein, and Tori Wilson – and their rivals: the Vandergeld sisters, Heather and Megan. Unbeknownst to Kevin and Marcus, they are being watched by colleagues, Vincent Gomez and Jake Harper, and their boss, Chief Elliott Gordon, who are undercover posing as hotel staff. At the hotel, pro basketball player Latrell Spencer is attracted to Marcus/Tiffany, and Kevin sets his sights on New York One News reporter, Denise Porter.
At the Vandergelds' annual charity auction, Latrell wins a dinner date at a restaurant with Marcus/Tiffany. While Latrell takes Marcus/Tiffany to a restaurant, Kevin, believing Denise likes rich men, pretends to be Latrell and takes Latrell's car to drive Denise to Latrell's house. There, he hears about Ted Burton turning the tables on Heather and Megan's father, Warren. With Kevin becoming romantically involved with Denise and Marcus/Tiffany unsuccessfully trying to reject Latrell, their combined antics put them under Gomez and Harper's suspicion.
At a nightclub, after winning a dance-off against the Vandergelds, Kevin and Marcus learn from Karen that Warren is penniless and has been taking loans from her father, meaning that Warren is the mastermind behind the kidnappings. The next day, the real Brittany and Tiffany arrive at the hotel and discover they are being impersonated.
The sisters arrive in the Hamptons, exposing their "clones", as does Marcus' wife, Gina, assuming that he is cheating on her. Realizing the Wilsons are being impersonated by men, Gomez and Harper aim to expose them, but inadvertently strip down the real Brittany and Tiffany in front of Gordon, resulting in the sisters punching Harper in the face. After Gomez and Harper are suspended, a furious Gordon fires Kevin and Marcus. Having lost both his job and possibly Gina, Marcus scolds Kevin for always dragging him into trouble.
Later, Kevin and Marcus discover that Warren had embezzled money through his charity. Marcus convinces Kevin to not tell Gordon, to redeem themselves with Gomez and Harper's help. Again posing as the Wilsons, they are chosen for the final fashion show. The Vandergelds are furious the Copelands/Wilsons have replaced them on the catwalk, but the real Brittany and Tiffany also perform in the event. Karen rejects the callous Heath, and Marcus punches him in the face. During the show, the Vandergeld sisters try to sabotage their "rivals", but end up being humiliated by Karen, Lisa, and Tori.
The real Brittany and Tiffany appear and expose Kevin and Marcus, causing mass confusion. Warren begins the kidnapping, but incorrectly captures Marcus/Tiffany and Brittany. This begins a fight between the Copeland brothers and Heath and Russ, accomplices in the kidnappings. Warren soon captures the real sisters and explains his financial troubles to his wife and daughters, unaware that his confession is being filmed. In the ensuing scuffle, Kevin is nearly shot trying to protect Denise, Latrell is shot trying to protect Marcus/Tiffany, and Kevin shoots Warren in the shoulder.
Marcus and Kevin capture Warren, while Gomez and Harper apprehend Heath and Russ. Afterward, their true identities are revealed, and Latrell is more dismayed that Marcus is not white, not that he is a man. Warren, Heath, and Russ are arrested, while Gordon reinstates the Copeland brothers, Gomez, and Harper. Marcus clears things with Gina, Kevin and Denise begin a relationship, and Latrell wins over the real Brittany and Tiffany. Tori, Lisa, and Karen admit they liked Brittany and Tiffany a lot more when Marcus and Kevin were them. The five agree to remain friends and go shopping the next day together.
Shawn Wayans as Kevin Copeland / Brittany Wilson
Marlon Wayans as Marcus Anthony Copeland II / Tiffany Wilson
Busy Philipps as Karen Googlestein
Jessica Cauffiel as Tori Wilson
Jennifer Carpenter as Lisa Anderson
Frankie Faison as Chief Elliott Gordon
Lochlyn Munro as Agent Jake Harper
Eddie Velez as Agent Vincent Gomez
John Heard as Warren Vandergeld
Jaime King as Heather Vandergeld
Brittany Daniel as Megan Vandergeld
Terry Crews as Latrell Spencer
Rochelle Aytes as Denise Porter
Maitland Ward as Brittany Wilson
Anne Dudek as Tiffany Wilson
Faune A. Chambers as Gina Copeland
Drew Sidora as Shaunice
John Reardon as Heath
Steven Grayhm as Russ
Casey Lee as Tony