This episode also marks the final appearance of recurring NCIS villain, Mamoun Sharif.
The body of a Marine Major is discovered in an underground sewer after a series of traffic lights begin acting rather crazily with a pedestrian discovering by chance that it happens to be an S.O.S message. When the NCIS team investigate, they discover that the victim was an unknowing test subject of a highly toxic and illegal chemical weapon, 10 kilograms of which have gone missing and are now in the hands of an enemy from their past. The team along with Army CID Lieutenant Col. Hollis Mann must find and stop Sharif before he unleashes the deadly gas all over Washington D.C.
On a street in downtown Washington D.C, businessman Allen J. Carter tells someone what do they think he said?
Carter remarks that he told Sydney and that she's more than welcome to freeze her own head when she dies but his is being cremated and scattered at the nearest Hooters.
Carter then remarks that he knows before stating Sydney is crazy.
As he stands at a crossroads, Carter remarks that even if it works, who wants to live forever?
Once the pedestrian sign goes green, Carter crosses while stating "Live fast, die young, you know?".
Suddenly, a SUV manages to stop short of hitting Carter with Carter dropping his stuff and yelling at the driver what the driver's doing and pointing out the sign said "walk".
Charlie Mills gets out of the SUV, angrily stating that his light was green.
The two glance around.
Suddenly, a traffic light is seen flashing its green light three times and sure, the other traffic light is doing the same thing.
Carter asks Mills if he's ever seen streetlight malfunctions like that.
Mills states that isn't a malfunction.
It's an SOS.
It then cuts to Carter and Mills who are glancing at the street lights, both men confused at what's going on.
In the bullpen, while Ziva and McGee are working, Mann and Gibbs discuss terrorist Mamoun Sharif whose photo then appears on the plasma. Mann tells Gibbs that Army CID was able to get an old lead from when Sharif was a paid informant working for the CIA.
She then tells him that the trail lead to an alias which led to a credit card and in turn, led to the bowling alley.
"Funny us running into each other like that", Mann states.
"Funny?", Gibbs states.
"Do you have a better one?", Mann asks.
"A few come to mind", Gibbs admits.
While this goes on, McGee looks stunned at the flirting going on between Gibbs and Mann while Ziva just smirks, amused.
Mann then wonders if their cases are connected. Tony then enters the bullpen, stating that they're connected just like McGee and his cute little writing pipe which has McGee closing his eyes in dismay.
Tony then reveals that the prints found on the computer to monitor the sewer where Major Maguire was match those on file from Sharif's CIA report.
"The Mad Bomber's back", Tony announces, confirming that Sharif's back in town.
"Except he's not building bombs", Ziva replies.
Mann wants to know where Sharif got the BZ gas.
While grabbing his coat, Tony states that one of Maguire's duties was to deliver small quantities of weapons-grade gas to civilian research labs.
Ziva tells Gibbs that she'll run down a list of the Major's deliveries starting with the most recent while Tony is to find out if any of them were BZ gas.
As Tony and Ziva leave, Mann wants to know if Gibbs teaches his team to finish his sentences for him.
Gibbs tells her that he teaches them to anticipate with Mann remarking that he must be a very good teacher.
Gibbs then thanks her by stating, "Thank you very much" Elvis Presley style with the two sharing a little moment.
McGee then interrupts by wondering if Sharif was covering his tracks, then why did he go to the trouble of killing Major Maguire?
Mann agrees, remarking that it is unusual that Sharif wasted the BZ gas as he did and while looking through the photos, Gibbs realizes that Sharif wasn't wasting the gas.
He was testing it.
Up in the office, NCIS Director Jennifer Shepard is having doubts about it. Gibbs tells her it's a chemical weapon and that she should guess. Jenny then states that if they've got anything specific like a date or a target.
Mann then admits that they don't have anything else.
Jenny wants to know if they've got any hard intel suggesting Sharif is planning an attack.
"You mean other than a dead guy in our morgue?", Gibbs asks.
"If you're worried about the lack of chatter", Mann begins.
"Don't", Gibbs finishes.
Mann then picks up by telling Jenny that the last time Sharif planned an attack, there was zero uptick in regards to the attack.
Jenny then states that Sharif proved last time that he was a pro at flying underneath their radar. Mann agrees before telling Jenny that even if Sharif isn't planning on using the gas himself but Gibbs interrupts her by stating that he'll sell it to someone who will.
After taking a minute to watch the exchange, Jenny then tells Gibbs that Homeland Security certainly love non-specific threats. Mann, however wants to know that since their investigations have merged, who's going to take the lead?
Jenny tells her that she'll be working under Gibbs and that Jenny herself and Mann's boss flipped a coin for it.
However, Mann and Gibbs aren't reacting, causing Jenny to wonder if there's a problem.
Mann assures her that there isn't but that she's just...
"Used to being on top", Gibbs responds.
Mann states in terms of command, that's true but she's happy to be working under or rather with Gibbs again.
Jenny then puts on her glasses and resumes looking at some papers but after catching Gibbs and Mann looking at her, she silently gestures for them to leave which they do.
Outside, on the balcony or stairway, Mann remarks that Jenny and Gibbs have worked together for quite a while.
Gibbs agrees but as they head down the stairway, Mann wants to know how long, causing Gibbs to stop and wonder if there's a reason why she's asking.
Mann tells him she's just curious before changing her mind and heading back downstairs.
As this goes on, Jenny emerges from her office and gives Gibbs a glance before heading into MTAC.
As Mann reaches the ground floor, she gives Gibbs a glance, causing Gibbs to smile in amusement at the situation concerning both his current and former girlfriends.
Tony and Ziva have arrived at the civilian research lab and are busy interviewing Wayne Gordon who tells them that his company upsized their operations after 9/11.
The interview is interrupted by Tony's cell-phone ringing and while he talks to the person at the other end, Ziva tells Gordon that Tony has two cell-phones, one for each ear.
Tony then tells them that he'll talk to them later before hanging up. Ziva remarks that it sounds like Tony has something up the wazoo, maybe a doctor's probe. Gordon tells them he's got a business to run and that they should direct their questions to the company's head engineer, Dane Hogan.
From first impressions, it's clear that Ziva's interested in Dane, something Tony picks up on.
As Gordon leaves, the two now turn their attention to Dane who asks them what they need.
Tony states that Ziva probably wants Dane's number, causing Ziva to give Tony a thump in the chest.
Tony tells Ziva that if she'd let it go, Dane would've thought Tony was kidding. Ziva then makes it clear that she doesn't want Dane's number. Dane asks her what she wants. Ziva then asks about the delivery of BZ gas they got last week while Tony scribbles something on a notepad.
Tony states that they need to confirm the shipment
Dane asks for the invoice which Ziva dumps on his desk in the form of a single page from Tony's notepad.
While Dane does a search, Tony wants to know since chemical weapons are banned, then are they doing research with them?
Dane tells them that not everyone plays by the same rules that they do, that they need to certify that their safety devices will work against a rogue attack and that the military provides them with the samples and certifies their devices and the company itself does the testing.
Dane then checks the manifest and confirms that they got 4 kilograms of BZ gas.Tony is confused, stating that according to SYSCOM records, it was 14 although Dane insists that they asked for four and that's what Major Maguire signed over to them which causes Ziva to realize that there are ten kilograms of BZ gas missing.
"Is that a lot?", Tony wonders.
Ziva doesn't responds but Dane instead gives Tony a gas mask.
While holding the gas mask, Tony produces his phone and then speed-dials a number, presumably to inform Gibbs of the development.
In the lab, McGee is talking about Mann and Gibbs to Abby who insists that McGee is reading too much into it.
Unsurprisingly, Gibbs and Mann then pop up, interrupting the proceedings while revealing that they were aware of what was going on.
While this happens, the program used to show what a couple's child would look like if they got together shows a baby.
McGee changes the subject by changing the program as Gibbs and Mann ask for an update concerning Sharif and Maguire.
Abby and McGee then reveal that they've been digging all day and that they've found something. As this goes on, Gibbs offers Mann a mint which she accepts.
Gibbs and Mann then realize that there was a twenty-thousand dollar that was wired from an offshore bank account two days ago.
As they talk, McGee and Abby study Gibbs and Mann just as Gibbs joins Abby, wanting to know if Sharif was the source of the wiring.
Abby tells him that Sharif didn't sign his name with McGee stating that if they can track the source, then that might give them a lead on Sharif.
Gibbs tells them to do it and he and Mann prepare to leave the lab but Abby calls them back, stating they've got more stuff to show them.
The two then get carried away with their technology.
"How long will they go on like this?", Mann asks.
"Until we stop them", Gibbs replies.
Mann then stops McGee by demanding that the Agent get to the bottom line. McGee then stops and tells them that they've got the video of Major Maguire that Sharif recorded just before Maguire died.
They then show the video with Abby revealing that Maguire first to pick the lock and then McGee reveals that Maguire even called for help.
McGee then speeds things up by stating that half an hour later, Maguire got the idea to try and signal using the power box on the wall which caused the traffic lights on the street to act strange.
Abby then tells them to watch what happens when the BZ gas begins taking effect.
It shows Maguire moving around the room.
Mann remarks that Maguire looks really agitated. McGee explains that the gas can cause severe hallucinations with Abby grimly informing them that Major Maguire is literally losing his mind.
It then shows Maguire collapsing to the ground, still holding his head.
In the lab, McGee, Mann, Gibbs and Abby look on, grim-faced with Abby stating that they now know how an eyeball got into Maguire's stomach.
Mann wants to know how much caused Maguire to lose his mind. A
bby tells them that it's roughly ten milligrams of exposure which has Gibbs and Mann looking at each other in dismay.
When McGee wants to know what's going on, Gibbs tells him that they're missing ten milligrams.
"That's like a million times more", McGee states.
With that, Gibbs, Mann and McGee leave the lab.
Upstairs, in the bullpen, Tony and Ziva have returned from the company.
Tony tells Gibbs that the company ran a full inventory with Ziva announcing that the BZ gas is the only thing unaccounted for.
Gibbs wants to know if they've found Sharif but Tony then admits that Sharif too is accounted for.
Gibbs states that Sharif's somewhere, doing something and that they should figure out where and find him.
Tony then suggests that they have a campfire, causing Ziva to react with dismay.
Tony then explains to Mann that campfire is where they get together in a free environment and discuss things without hugging.
Unfortunately, Gibbs isn't the mood for a campfire and abruptly leaves the bullpen.
Mann wants to know where Gibbs is going with McGee telling Gibbs is going to the same place he always goes to think.
With that, Tony, Ziva and McGee return to their desks, leaving Mann confused.
As it turns out, Gibbs is in his basement, working on his boat when Mann arrives in, telling him that Sharif has made it to the top of every agency's most-wanted list and that Homeland Security's all over it.
Gibbs, however doesn't respond.
Mann then asks Gibbs where his boat is.
"Had to move it to make some room", Gibbs replies.
Mann's stunned but before she can say anything, Gibbs tells her that the other agencies are covering their asses and that it's going to take them days to do anything.
Mann tells him they want a briefing because chemical weapons are notoriously difficult to deal with and ten kilograms is a large amount before stating that it could be a land-based attack.
"Or something else we haven't thought of yet", Gibbs replies.
Mann tells him that what she's here for.
"Is it?", Gibbs wonders.
Mann then states that it looks like Gibbs was expecting something else or is he hoping?
Gibbs wants to know what she has in the bag.
Mann tells him it's dinner and Gibbs tells her that why don't they start with that? As Mann begins unpacking the food, she voices her belief that Sharif might sell the BZ gas but Gibbs disagrees.
When Mann asks why, Gibbs tells her it's in Sharif's eyes because Sharif isn't interested in the money, he only wants to kill.
Mann wonders who given that Sharif's sold himself out to the highest bidder his whole life, no matter which side they were on and she also wants to know what's changed.
Gibbs tells her that as people get older, they realize they want something different. Mann wonders if Gibbs can tell this just by looking into someone's eyes with Gibbs telling her that he can.
Mann asks Gibbs what he sees in her eyes with Gibbs stating that she wants him to kiss her.
"So are you going to?", Mann asks.
"Yeah", Gibbs replies.
"When?", Mann asks.
"After we catch Sharif", Gibbs states.
Mann agrees and tells him that she'd better go before she changes her mind. She then tells him that they're a distraction to his team and that they can't have anything interfering with finding Sharif.
Gibbs states that they're gonna find him but what happens when they do?
"Interfere", Mann replies and leaves the basement just as Gibbs smiles with the moment being interrupted by Gibbs's cell-phone ringing. He then takes down a jar and empties the contents including the ringing cell-phone before answering it but it's not his team.
It's Sharif himself.
It then cuts to Sharif who's driving along a road or motorway while talking to Gibbs.
The two exchange comments before Sharif gets down to business. He knows that they know that Sharif has ten kilograms of BZ gas in his possession, only to get silence.
Gibbs wants to know what Sharif wants.
Sharif tells him that the United States government are holding six alleged members of a Chechen separatist group in a secret place in Afghanistan and Sharif states that he wants the members released within the next 24 hours.
Gibbs tells Sharif that it isn't going to happen.
Sharif states that it's because the U.S doesn't negotiate with terrorists but Gibbs misunderstands him with Sharif stating that they're not negotiating.
Sharif wants the men released or he'll release more of the BZ gas.
Gibbs is confused.
Sharif then tells him that it's hard to determine how many have been exposed and that airborne weaponry is a tricky business before telling Gibbs that he's certain that the 11pm news will have a good figure by now.
Gibbs switches on the TV and finds that the ZNN channel is running a report on it, only for it to be noted as being a mystery illness instead of BZ gas, presumably to stop everyone from going into a mass panic. The report states that no-one's died yet but that at least six people have fallen ill.
"Actually, counting you, Agent Gibbs, that makes seven", Sharif replies.
It then cuts to Gibbs who pulls the phone aside while staring at the TV, stunned.
- It's revealed that six months have passed since the events in "Hiatus Part 1" and "Hiatus Part 2".
- After Ducky mentions that Major Maguire's eye was found in his stomach, Gibbs asked if he also found a toe. This refers to when Ducky found a toe in the stomach of suspected serial killer Charles Bright in the earlier episode, Smoked (episode).
- The hand tools that Gibbs is using in this episode are really some of Mark Harmon's real tools that he uses when he is doing carpentry in his shop.
- The bowling alley that the NCIS team visit and unknowingly find the Army CID team there is also the same one Caitlin Todd and Tony visited in the Season 2 episode, Witness (episode). Also, while in the bowling alley, Bob Dylan- Things Have Changed is heard playing in the background.
- The flashbacks Gibbs experiences while under the influence of BZ gas are from the Season 3 finale episodes, Hiatus Part 1 (episode) and Hiatus Part 2 (episode).
- The Morpho-Program from Singled Out (episode) makes a reappearance, most notably in the scene where Abby and McGee are talking about Gibbs and Mann in the lab.
|Leroy Jethro Gibbs||Mark Harmon||NCIS Special Agent in charge of the NCIS Major Case Response Team.|
|Anthony DiNozzo||Michael Weatherly||Senior Special Agent and second-in-command of the NCIS Major Case Response Team.|
|Ziva David||Cote de Pablo||Mossad Liaison to the NCIS Major Case Response Team.|
|Abigail Sciuto||Pauley Perrette||Chief Forensic Specialist, NCIS.|
|Timothy McGee||Sean Murray||Junior Agent of the NCIS Major Case Response Team.|
|Jennifer Shepard||Lauren Holly||NCIS Director.|
|Donald Mallard||David McCallum||Chief Medical Examiner, NCIS.|
|Dr. Jeanne Benoit||Scottie Thompson||Tony's girlfriend.|
|James Palmer||Brian Dietzen||Ducky's assistant.|
|Hollis Mann||Susanna Thompson||A Lt. Colonel with Army CID|
|Mamoun Sharif||Enzo Cilenti||A CIA informant and terrorist.|
|Dane Hogan||Victor Webster||A scientist working in the civilian research lab.|
|Allen J. Carter||David Starzyk||A businessman who notes that the lights are acting strange at the beginning of the episode.|
|Wayne Gordon||Rob Brownstein||The head of the civilian research lab.|
|Charlie Mills||David Barrera||A man who realizes that the traffic lights are acting weird but instead discovers that it's an SOS.|
|John Maguire||Sean Bunch||A Marine Major and the victim.|
|Jack Reynolds||Brandon Molale||A Special Agent with the Army CID.|
|Newscaster||Patricia Mizen||Uncredited role.|