An uptight and by-the-book FBI Special Agent is assigned to take down a ruthless drug lord. She's a perfectionist with a spotless reputation and a penchant for doing things her way. Her world is turned upside down, however, when she's forced to team up with a foul-mouthed, tough-as-nails Boston cop who has never had a partner or a friend. This cop doesn't just break the rules; she tramples them. Unbeknownst to the disciplined agent, her superiors send her out not only to apprehend the kingpin but also to determine whether the Boston detective has become too reckless to continue as a police officer.

As they begin their investigation, the mismatched partners struggle to coexist, much less work together. With the FBI agent's methodical approach clashing against the detective's street-smart tactics, it seems like their mission is doomed to fail from the start. But as they dig deeper into the city’s criminal underworld, mutual respect begins to grow. They find themselves relying on each other's unique skills to navigate a maze of crime and corruption. In order to take down the drug lord threatening the city, they must find a way to blend their polar-opposite personalities and styles, before they end up killing each other or botching the case entirely.