Gaylord Oakes (ANTHONY HOPKINS) and Kevin Pope (CHRIS ROCK) are undercover CIA agents working out of Prague where they're attempting to complete the purchase of a nuclear suitcase bomb from Russian black market dealer Adrik Vas (PETER STORMARE). Working under the guise of antiquities dealer Michael Turner, Pope has set up the deal, but is murdered during a shootout with other parties who are desirous of the bomb.
Realizing they need Kevin to finish the deal, CIA director Roland Yates (JOHN SLATTERY) orders Oakes and his associates, including agents Seale (GABRIEL MACHT), Swanson (BROOKE SMITH) and Carew (DANIEL SUNJATA), to pick up New York ticket scalper Jake Hayes (CHRIS ROCK) and see if he'll help.
It turns out he's Kevin's long lost twin brother who's been scraping by, trying to make ends meet and keep his girlfriend, Julie (KERRY WASHINGTON), from moving across the country and taking a job with her ex-boyfriend.
After some negotiations, Jake agrees to the deal, but isn't told the specifics or related dangers of what he'll have to do or who he'll be dealing with, including heavies Dragan Adjanic (MATTHEW MARSH) and Michelle Petrov (DRAGAN MICANOVIC), or Kevin's beautiful ex-girlfriend, Nicole (GARCELLE BEAUVAIS-NILON), who wants to get back together with him.
With only nine days to learn how to mimic his dead brother's mannerisms and knowledge in order to fool Vas and the others, Jake sets out for Prague with Oakes and his crew, unaware of the potentially deadly ramifications should they fail in their quest.