Danny and Jackie are assigned to protect a key witness in a Russian mob trial, but when an attempt is made on her life, they realize there is a leak on the task force. Meanwhile, Erin is offered a job as deputy mayor, which would have her working directly with her father.
Frank Reagan is the New York Chief of Police and patriarch of the Reagan brood, which he heads as diplomatically as he does the force, even when dealing with the politics that plagued his unapologetically bold father, Henry, during his stint as Chief. A source of pride and concern for Frank is his eldest son Danny, a seasoned detective, family man and Iraqi War vet who on occasion uses dubious tactics to solve cases. The sole Reagan woman in the family, Erin, is a N.Y. Assistant D.A. and newly single parent, who also serves as the legal compass for her siblings and father. Jamie is the youngest Reagan, fresh out of Harvard Law and the family's "golden boy".
However, unable to deny the family tradition, Jamie decided to give up a lucrative future in law and is now a newly minted cop, a career change seemingly supported by his beautiful girlfriend, Sydney Davenport, a first year lawyer. Jamie's life takes an abrupt turn, however, when he's asked to become part of a clandestine police investigation even his father knows nothing about, and one that could impact the family's legacy.