Blue Bloods' Bridget Moynahan came back to Boston Blue to direct an episode where Donnie Wahlberg's onscreen son makes a DUI arrest. In Us Weekly's exclusive clip from the Friday, December 12, episode of the hit CBS series, Jonah (Marcus Scribner) and Sean (Mika Amonsen) are on shift when they notice an unruly driver. They arrest the man - who is evidently drunk - but realize he is a member of the FDNY.