All 22 episodes from the fourth season of the US drama series following a family of New York cops headed by Frank Reagan (Tom Selleck). As well as the head of the family, Frank is the New York City Police Commissioner, following in the footsteps of his father, Henry (Len Cariou). Frank's children also share his passion for law and order: Danny (Donnie Wahlberg) is an NYC detective, Erin (Bridget Moynahan) works in the District Attorney's office and Frank's youngest child Jamie (Will Estes) works undercover. The episodes are: 'Unwritten Rules', 'The City That Never Sleeps', 'To Protect and Serve', 'The Truth About Lying', 'Lost and Found', 'Growing Boys', 'Drawing Dead', 'Justice Served', 'Bad Blood', 'Mistaken Identity', 'Ties That Bind', 'The Bogeyman', 'Unfinished Business', 'Manhattan Queens', 'Open Secrets', 'Insult to Injury', 'Knockout Game', 'Righting Wrongs', 'Secret Arrangements', 'Custody Battle', 'Above and Beyond' and 'Exiles'.