The NCIS team suspects foul play when a Navy Lieutenant is the victim of radiation poisoning.

Gibbs and the team collaborate with the ailing Lieutenant, who is an inspector for the International Atomic Engery Agency (IAEA), as they recreate his routine in an effort to figure out when the contamination took place. Gibbs is convinced that whoever is responsible for poisoning the Lieutenant was trying to ensure that his next scheduled inspection would not happen. But when the dying man insists that only his two closest colleagues knew of the upcoming trip, the team works to find the culprit. Meanwhile, Tony is surprised when he sees a softer side of Ziva.