With information received from Mossad, NCIS successfully capture an international arms dealer and they soon discover that "ARES", a highly classified weapons system, will be sold to an important and mysterious arms dealer known as "La Grenouille". The team then realize that if they want to stop the deal from going ahead, they will need to send someone undercover and that someone is none other than Ducky.
Eli Lisack emerges from a jeweler's shop and heads to grab a paper.
As he does that, the window of a black van unrolls and a camera lense is seen with Goliath himself being focused on.
The camera takes a few photographs of Goliath who looks up.
Unnerved by the feeling the people in the black van are watching him, Goliath heads off.
In the van, the driver gets the engine while the driver's partner produces a gun.
Goliath continues walking down the street just as the black van leaves its parking spot.
In an attempt to throw it off, Goliath slips behind a huge green gate and watches as it drives past. However, he starts running once the van's tyres are heard screeching, suggesting that those inside have spotted him.
As the van reverses, Goliath makes a run for it with the van in hot pursuit.
Almost instantly, Goliath rushes down an alleyway, the van right behind him.
Once he gets to the gate, Goliath attempts to jump but he can't move or budge any further while behind him, the van comes to a screeching stop.
Suddenly, two people clad in dark clothing appear behind Goliath, both tugging at his legs and as Goliath is dragged back down while protesting, the two drag him to the van.
After they've handcuffed him, one places a tap over Goliath's mouth while the other places a bag over his head with Goliath begin dragged into the back of the van.
One returns to pick Goliath's dropped bag.
As they get into the van, the door slamming shut, Goliath is still protesting and is held down by one of the mysterious figures while another injects him, presumably with a sedative.
Once Goliath has been knocked out, they leave him there.
It then cuts to the main area of the van where the two figures head there and as they sit down in their respective seats, they then pull off their masks, revealing themselves to be none other than NCIS Special Agent Anthony DiNozzo and his partner, NCIS/Mossad Liaison Officer, Ziva David.
In the bullpen, McGee explains that the area they're heading to is Aeroport de Sherbrooke, south-eastern Quebec and that it's thirty miles across the border from New Hampshire which means that La Grenouille will be right in NCIS's backyard.
"Did I miss Quebec becoming the 51st state?", Gibbs asks.
"I'm not going to watch that bastard fly again, Jethro", Jenny states.
"Again?", Gibbs says before heading back to his desk.
- Ducky goes undercover for the first time.
- Gibbs and the team eventually learn about the operation that Tony and Jenny have been working on: to track down arms dealer René Benoit aka La Grenouille/The Frog, an international arms dealer.
- During a talk with Gibbs in MTAC, Jenny reveals that she's been trying to bring "La Grenouille" down for ten years.
- It's revealed that in stressful situations, Ziva reverts to her Mossad training.
- The team learn about 'La Grenouille'.
- It's also revealed that Trent Kort is actually an agent for the C.I.A.
- In the scene where the team is trying to break Goliath, there is a moment when Goliath talks about Ares. Tony answers with Cancer, Gibbs with Virgo, and Ziva with Scorpio. These astrological signs are the same birth signs as the actors who play the parts (i.e. Michael Weatherly is a Cancer and Mark Harmon is a Virgo while Cote de Pablo is a Scorpio).
- "Charles Harrow" was played by actor Fred Tate, who closely resembles David McCallum and has "stood-in" for him before. In the episode "The Meat Puzzle (episode), Tate plays a corpse made to resemble Ducky.
- Armand Assante is credited as a Special Guest Star.
- In the Region 2 DVD, after the phoof of McGee calling for medical attention, the next phoof of Jenny standing in the squad-room is missing.
- NCIS threatens to take Lisack to Zaire but this may be a show research blooper as the Democratic Republic of Congo has not been called Zaire since 1997.
|Leroy Jethro Gibbs||Mark Harmon||NCIS Special Agent in charge of the NCIS Major Case Response Team.|
|Anthony DiNozzo Junior||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.|
|Cynthia Summer||Stephanie Mello||Jenny's secretary.|
|Trent Kort||David Dayan Fisher||An agent with the CIA.|
|Martin Quinn||Corey Stoll||An arms dealer.|
|Regine Smidt||Sandra Hess||An arms dealer.|
|René Benoit||Armand Assante||An international arms dealer originally from France.|
|Eli Lisack||Assaf Cohen||An Israeli-born arms dealer.|
|Nick Hurley||Jim Parrack||A man who appears in the episode.|
|Max Phillips||David Batiste||Hurley's friend.|
|Charles Harrow||Fred Tate||A retired weapons dealer responsible for designing ARES- a weapons system. Later dies from a heart attack after being chased by McGee and Ziva.|
|Rose O'Leary||Serena Scott Thomas||An Northern Irish arms dealer known as "Black Rose". Uncredited role.|