As Decima uses Samaritan's feeds to hunt Reese and Shaw, Greer exploits Finch's greatest weakness in an attempt to lure him out of hiding: his love for his former fiancée, Grace Hendricks.

The team takes desperate actions in its race to prevent the malevolent AI program Samaritan from coming online and making them its first targets. Meanwhile, the months-long battle with the anti-surveillance terrorist group Vigilance comes to a shocking conclusion.