With information from Mossad, NCIS are successful in capturing an international arms dealer and they discover that "ARES", a highly classified weapons system will be sold to an arms dealer known as "La Grenouille," an important arms dealer. The team then realize that if they want to stop the deal from going ahead, they need to send someone uncover and that someone is none other than Ducky.
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.
This is also the only Season 4 episode that doesn't have a phoof after the opening credits.
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.