Agenti DiNozzo a Ziva unesou za bílého dne občana Izraele. Jedná se o tajnou misi pod vedením Gibbse. Izraelčan má přezdívku Goliáš a je dealerem zbraní. Vyšetřovatelé se ho chystají vydat do Konga, kde ho nečeká nic dobrého. Goliáš je ochoten spolupracovat výměnou za informace. Prozradí, že Ares - satelitní naváděcí systém amerického námořnictva je na prodej na černém trhu a zná prodejce.

Autorem Aresu a prodejcem je Charles Harrow. Timothy a Ziva ho jedou k němu domů zatknout. Mezitím DiNozzo zjistí v Harrowových e-mailech kontakt na Trenta Korta. Problém je v tom, že ho zná, jelikož na něj byl nedávno nasazen Gibbsovou nadřízenou Jenny Shepardovou, ale o celé operaci se nesměl dozvědět Gibbs, který však začíná něco tušit. DiNozzo spěchá za Shepardovou, aby ji sdělil svůj objev. Shepardová okamžitě vydává Gibbsovi příkaz, aby nezatýkali Harrowa a svoje lidi odvolal. Tím však Gibbsovi musí odhalit to o čem neměl vědět. Mezitím jsou Timothy a Ziva odvolaní a mají pouze sledovat Harrowa. Harrow je oba odhalí a dá se na útěk. Při útěku dostane infarkt a umírá.

Abby s Timothym naleznou software Aresu a samotný Ares, který měl být předmětem koupě na černém trhu. Nejvyšší nabídku navrhl La Grenouille, se kterým má Shepardová nevyřízené účty z minulosti. Vyšetřovatelé zjistí, kde se má uskutečnit předání Aresu. Problém je v tom, že Harrow je mrtev. Doktor Mallard je pověřen, aby dojel na místo předání v utajení za Harrowa a předal La Grenouilleovi kopii Aresu, ve které je uložen virus trojský kůò. Operace probíhá podle plánu. Ziva, která je nedaleko místa střetnutí má La Grenouilleho na mušce a čeká na rozkaz od Shepardové k jeho zneškodnění. V posledním okamžiku má však Shepardová telefon a rozkaz ke zneškodnění nevydá. La Grenouille opět proklouzne a odlétá.

Vyšetřovatelé byli podvedení CIA, která měla vše pod kontrolou a nepřála si La Grenouilleovu smrt. Charles Harrow a Trent Kort byli agenty CIA, o kterých NCIS nevěděla.

NCIS agents Ziva and DiNozzo kidnap an Israeli arms dealer (nicknamed "Goliath") who has been selling his merchandise to terrorists. They inject him with a knockout serum. He wakes up in a jet, with Gibbs, DiNozzo, and Ziva telling him that he is going to be turned over to the President of Zaire for selling his military malfunctioning weapons. He tells them that he knows who is selling the US government's secret cruise missile targeting system, named "ARES", after the Greek God of War. He will tell them who it is in exchange for returning to Washington DC. Off-camera, he has apparently told them the seller's name, but he discovers that they never left DC.

During a search of Goliath's e-mails from his computer, of which he gave NCIS the user ID and password, Dinozzo discovers a photo of a man he had photographed during an undercover operation for Jenny eight weeks ago. Since Dinozzo is under orders not to reveal the details of that operation to anyone, including Gibbs and the rest of the NCIS team, he feigns ignorance to Gibbs, and goes to the Director to report the photograph to her. The man in the photo is identified as Trent Kort.

Ziva and McGee tail the seller of the ARES system, Charles Harrow. After spotting them, he tries to run away, but has a heart attack and dies. Later, after entering Harrow's home, the two find it filled with sophisticated computer equipment.

After bringing Harrow's equipment to NCIS in Abby's lab, she and McGee find the ARES microchips stuffed into condom packets, while the main hardware is disguised as a twenty year old computer that has been retrofitted to modern standards. Needing to find out who the winning bidder of the ARES system is, McGee realizes that Harrow used an Internet cafe where he and Ziva had spotted him, earlier. Using an apparently illegal technique, McGee uses the NCIS computers to track the e-mail Harrow had sent from the cafe to the winning bidder, who turns out to be "La Grenouille" (French for "The Frog"), a man the Director has been after for over a decade.
Since Harrow is dead, NCIS needs to find an agent with a British accent who can go undercover as Harrow. Dr Mallard fits the bill perfectly. The e-mail that McGee found indicates that the exchange is to take place in Quebec in five hours. The Director calls in a favor, apparently to Quebec authorities.

Later, in Quebec, Ziva and Dinozzo are set as snipers to protect Dr Mallard and to kill "La Grenouille", who they believe is the man in the photograph from Harrow's e-mail. After Dr Mallard passes a check by one of the "La Grenouille's" henchmen, he is directed to a jet where the scruffy-looking man from the photograph appears. Via a tiny transceiver in his ear, Dr Mallard listens to instructions from the NCIS team, who are well hidden nearby. They tell him to give the ARES hardware to the man's female assistant for testing. When it proves to be genuine, the man makes an elaborate sweeping motion using his cellphone light. It is a signal, from which a well-dressed man appears from the shadows. It turns out to be "La Grenouille", who used the other man as a decoy, in case something went wrong. Convinced that Dr Mallard is Harrow, he offers Mallard a drink of 200 year old Cognac. Afterwards, they exit the car, with "La Grenouille" about to board the jet. The NCIS Director is about to order Ziva and Dinozzo to shoot him, when she receives a phone call on her cell phone, at which point she quickly orders them to stand down. The scruffy man comes out of the jet and hands Dr Mallard a bag of diamonds as payment, but then suddenly pulls the NCIS transceiver from Dr Mallard's ear and, speaking into it, asks if NCIS got the message. The NCIS Director acknowledges that they did, so the man returns to the jet. It turns out that he is a CIA operative.

The episode ends with the NCIS Director pouring the diamonds onto her desk as Gibbs enters her office. She tells him that ARES had been rendered useless by a computer virus.