This American police procedural follows the Reagans, a family of police officers working with the NYPD. Frank Reagan (Tom Selleck) is the police commissioner and a former U.S. Marine. His three grown children include the hard-nosed top NYPD detective Danny (Donnie Wahlberg), assistant district attorney Erin (Bridget Moynahan) who prosecutes most of the offenders that Danny arrests and recent Harvard Law School graduate and rookie police officer Jamie (Will Estes). Frank's second son Joseph was an NYPD detective investigating a group of corrupt cops operating an organization called the "Blue Templar," who murdered Joe in the line of duty. Along with Frank's father and former NYPD commissioner Henry (Len Cariou), the family lives through the troubles of work and home life.