After a civilian research vessel in the North Atlantic picks up a small boat of wounded Navy officers, NCIS arrives on the ship and is forced to hide after discovering terrorists on board. Also, Agent Knight takes a paper doll with her on the mission to capture photos for her niece's grade school class.

While investigating the death of an intruder at Quantico, Jimmy and Kasie are exposed to a deadly biotoxin, and the NCIS team calls on Doctor Carol Wilson for help as they race to find the antidote. Also, Torres tries to distract Jimmy's daughter, who came to the office to spend the day with her dad.