Blue Bloods - Season 5 Episode 21 New Rules Honor. Justice. Family. It’s in their blood.
Overview: When NYPD Deputy Chief Donald Kent, a commanding officer of the gang division, and his wife are gunned down in an apparent gang hit, Frank orders all hands on deck to catch his friend’s killer. Working the case, Danny and Baez go see Mario Hunt, a well-known member of a deadly gang, in the first of a two-part season finale.