NEW YORK CITY POLICE Commissioner Frank Reagan (Tom Selleck) has a lot to be proud of... but his greatest pride is his family. His oldest son Danny (Donnie Wahlberg) is a streetwise detective who always gets the job done...even if that means bending the rules. As an Assistant D. A., his daughter Erin (Bridget Moynahan) passionately defends the letter of the law while she struggles to raise her daughter as a newly single mother. His youngest, Jamie (Will Estes), just enlisted as a beat cop even though he earned a degree from Harvard Law. The Reagans have a proud tradition of service to the city, but they also have a habit of making waves, as exemplified by Frank's father Henry (Len Cariou) - an outspoken former Commissioner whose career ended because of his bold opinions. Police work is more than just a job in BLUE BLOODS.