Narcotics cops Mike Lowrey (Smith) and Marcus Bennett (Lawrence) head up a task force investigating the flow of ecstasy into Miami. Their search leads to a dangerous kingpin, whose plan to control the city's drug traffic has touched off an underground war. Meanwhile, Mike has been secretly seeing Syd (Gabrielle Union), Marcus's sister. Mike and Marcus discover that Syd is working undercover for the DEA. Soon her cover is blown and she ends up being kidnapped by the dangerous kingpin. Now they have to rescue Syd from Cuba and take down the well known drug dealer once and for all.