Continuing this week is the fourth season of the hit drama series following a team of special agents who investigate Navy and Marine Corps-related crimes. In this episode, the agents probe the murder of a marine major trapped in a sewer. It soon becomes clear that he was killed by a chemical weapon that has fallen into the hands of a vengeful terrorist.

Gibbs and the team are called to an underground maintenance room where the body of marine Major John McGuire has been found with his eye scratched out. There are no other obvious signs of trauma, but Ziva is disturbed to discover a webcam positioned on the wall to record the scene. “Whatever happened, someone wanted towatch,” she says.

Ducky’s autopsy reveals that McGuire died of organ failure brought on by excessive body temperature. “His body literally became too hot to handle,” he says. In his distress, the major tore out his own eyeball and swallowed it. Abby’s tests reveal that McGuire was poisoned by a chemical weapon called BZ, which can cause excessive body heat, hallucinations and finally madness. McGuire worked for a unit that researches chemical weapons, and may have come into contact with BZ when he delivered it to a laboratory.

McGee follows the webcam feed to a computer at a bowling alley. The agents race to the scene only to find it is already under the surveillance of Homeland Security. Gibbs encounters Lt Col Hollis Mann, who says she is still on the trail of Mamoun Sharif, the terrorist who planted a bomb at a naval golf course (see the episode ‘Sandblast’). Fingerprints from the bowling alley confirm that Sharif is connected to Major McGuire’s murder, and the NCIS team is left facing the possibility that he is planning to use BZ
gas in a large-scale attack.

Tony and Ziva trace the lab that received the BZ from McGuire, and the chief engineer, Dane Hogan, tells them the major only delivered 4kg of BZ. Around 10kg of the substance is still missing and could be in Sharif’s possession. Sharif then intervenes personally when he calls Gibbs and demands the release of six Chechen terrorists. To show what he is capable of, Sharif reveals that six people have already been infected with BZ – and even claims to have poisoned Gibbs.

Tests soon confirm that Gibbs is free of contamination, while the six other victims were only exposed to a low dose. “Sharif appears to be bluffing,” Ducky says. Abby, meanwhile, provides another lead when she discovers that Dane Hogan was responsible for wiring money to Major McGuire’s account. The scientist is hauled in for questioning and forced to admit that he gave the BZ gas to Sharif, and that he tried to cover his tracks by implicating the major in the plot. “We weren’t planning on killing anyone,” he explains.

“The plan was to scare people.” Hogan wanted to create enough panic to send shares in his research company soaring, allowing him to cash in. “I’ll be a millionaire by tomorrow’s bell,” he says. Hogan insists that he rendered the gas inert before handing it over to Sharif, but Gibbs thinks the terrorist has found a way to reactivate it. “It wasn’t harmless for Major McGuire and those six people,” he points out. Ducky and Abby realise that Sharif has mixed the BZ into a solvent that is absorbed straight into the bloodstream. An object only needs to be coated in the substance for it to become deadly. The team realises the extent of Sharif’s plan when he starts withdrawing large amounts of money in small notes from different banks. “He’s putting the BZ on the money!” Col Mann says. If Sharif is allowed to spread the infected cash, thousands of people could be at risk. But can they track him down in time?

Friday February 29 at 9:00pm on five