Much to everyone's shock, Abby is caught by local police planting what is revealed to be a real bomb and real sarin gas at a concert event.
It is revealed that she was participating in a Homeland Security terrorist attack think tank project, working out how real terrorists might conceivably work around security precautions to pull off an attack.
Unfortunately, the Homeland Security agent who recruited her and the other members of the think tank soon turns up dead, and it looks like he was behind it all.
To make matters worse, Homeland Security discovers that their files have been compromised, and dozens of such think tank attack plans and response strategies -- essentially DHS's terrorist attack response playbook -- have been stolen.
The team realizes that the supposed terrorist attack was actually targeting someone, and determine that the intended target was a Bosnian politician.
It was none other than the DHS agent's aide who manipulated the think tank to kill the Bosnian, who was responsible for the death of his family years before.
The problem then becomes to find what happened to the terrorist playbook stolen from DHS: who stole it and how to find it before it finds itself into the hands of the very people it was written to combat.
To that end, Gibbs dispatches Torres and McGee to New Orleans to track down the source of the hack and stop the sale of the playbook.