If you've been following this show from the beginning, like I have, you probably enjoy it for the relationship dynamics, the interactions, and the sense of family. The investigations, the politics, and the other nuances supplement and compliment the before-mentioned.
Tom Selleck was the one who requested that the "family dinner" be added in order to give the show that sense and strength in family. This turned out to be a masterful stroke, as some of the show's deepest, touching, and most poignant discussions have occurred in these short scenes.
Therefore, it makes it all the more profound and apt that what happens at the end of this season finale, also happen at the family dinner table.
Danny, Erin, Frank, and Jamie are all connected in investigating a series of drive-by shootings that are all connected to a past case at the beginning of Frank's tour as PC. When it becomes clear as to who is behind it, and why, one of the Reagans's life will be put in danger. We already lost Linda, and now we had to wonder if we might lose another member of the family.
The chemistry between these actors is powerful, and it is the driving force of this show. Danny and his partner, Frank and his staff, and Jamie and Eddie, the family connections, notwithstanding.
For any true Blue Bloods fan, this season finale episode was arguably the best one yet!