In Rota, Spain, three off-duty sailors are carousing at a bar when one — Petty Officer First Class Wilkes (guest star CHARLIE HOFHEIMER) — suddenly goes berserk. A little later he is discovered hanging, in the nude, in the bar’s walk-in freezer, with a 106 degree body temperature and, unfortunately, obvious symptoms of a long-term methamphetamine addiction. Aboard Wilkes’ ship, the USS Enterprise, one of Gibbs’ (MARK HARMON) former charges, Agent Burley (guest star JOEL GRETSCH), needs his help in figuring out how supposedly squeaky-clean Wilkes has ended up in critical condition. In recent, random drug testing, Wilkes always tested negative. But the type of behavior he exhibited — and the tox report confirming meth in his bloodstream — are synonymous with long-term drug use. The ship is on its way to a search and rescue mission, set to reach its destination in less than two days, and — if there’s a drug problem on board — the ship’s Captain needs the situation immediately remedied for everyone’s safety.
Now on Enterprise, Gibbs, Tony (MICHAEL WEATHERLY) and Kate (SASHA ALEXANDER) disperse to question the involved parties. Gibbs takes on a recovering Wilkes, Kate talks with Wilkes’ fellow arresting gear crewmen, Petty Officers Niles (guest star JONATHAN T. FLOYD) and Shrewe (guest star ANSON SCOVILLE), while Tony interrogates their chief, Reyes (guest star CARLOS GOMEZ). But all that they determine is how all three crewmen unequivocally shun drugs and how dedicated Reyes is to his men and having them do the best job possible. In addition, room searches turn up nothing. On Gibbs’ orders, Burley begins scanning flight deck tapes of Reyes and his crew during ops for any signs of suspicious behavior. Just as little headway seems to be made, Shrewe succumbs to the same behavior Wilkes did — on- deck during a flight landing — and lands in sickbay as well. Like Wilkes, Shrewe also always had tested negative in recent, random drug testing.
However NCIS’ mission soon takes an even more sobering turn when Wilkes dies, prompting Gibbs to send his body to Ducky (DAVID McCALLUM) for an autopsy. While Ducky performs that, Abby (PAULEY PERRETTE) goes to work analyzing samples provided by the ship’s urinalysis coordinator, Lt. Norski, from recent drug testing. Gibbs and Burley still study hundreds of hours of flight training tapes and finally do spot a suspicious move in one of them: Reyes seems to be surreptitiously handing off something illicit to Wilkes. Enhancing the image, Gibbs can ascertain that Reyes’ hand- off seems to be a pill. While Reyes confirms his action, he says the pill is nothing more than over-the-counter Alert, consisting mostly of caffeine, since his men can’t have coffee on-deck. And, when Reyes’ Alert pills are tested, they are, in fact, determined to be just that.
Ducky informs Gibbs that Wilkes didn’t die due to the drug abuse; he was actually murdered when someone squeezed air into his IV, causing immediate cardiac arrest. Then, Abby gives them the revelation that the supposed different urine samples from Wilkes and Shrewe are clean... and actually the same. With the case getting that much more complicated, and the Enterprise nearing its search-and-rescue destination, Gibbs begins focusing again on the Alert pills and a once-unlikely culprit. Realizing Niles may still have some of the “Alert” pills that Reyes doles out, Gibbs asks for one. When that is tested, it comes back as meth; Gibbs realizes that Reyes has been “filling” the Alert ones with meth, and then handing them out to his unwitting crewmen. The team also learns that both Reyes and Norski have worked together on three ships. That history that explains how urine samples that would have tested positive for drugs have been coming back clean. Then Giles sets up a ruse: an ostensibly fatigued Niles tells Reyes he is too beat for upcoming ops on deck, so the chief hands him some pills. As he does, Gibbs emerges... and Reyes knows he has been caught. To a disgusted Gibbs, Reyes admits his guilt but incredibly insists he had to give his men these pills to help them do their jobs better — even if it meant that Wilkes became a “casualty of war.”