Ducky goes undercover to stop the sale of the navy's new weapons system to an arms dealer.
The murder of a marine brings the team into contact with the Office of Special Projects in LA. Tony becomes concerned about Ziva's behaviour.
The death of a marine unearths a top-secret military research programme. Meanwhile, Abby is called away to assist with an ongoing medical project.
The team learns that ten kilos of highly toxic chemical weapons have fallen into the hands of a terrorist and races against time to stop him.