After getting a match from an unknown relative from a DNA network, Sean Reagan does some detective work to figure out who this mystery person might be. Frank gets a personal request from a woman to transfer her son to a safer assignment. Also, Danny seeks to uncover the truth behind the hug of a key witness in one of Erin's cases, and Eddie begins to think about having a child after she and Jamie discover a newborn left outside their precinct.
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.