Caitlin “Cat” Sullivan serves as a detective for the NYPD in Brooklyn. When her license is revoked, she turns to Leo Romba, a talented cab driver from France, to be her chauffeur and assist her with her investigations. As they work together to crack cases, Cat is also secretly probing into her father’s murder, a fellow NYPD detective believed to have been killed by the Capella crime family. Her pursuit of the truth puts her at odds with her superior, Captain Baker, and her former husband, Gregg, who is now handling the case for the FBI.