Gibbs and Ducky recall the case that brought them together on NCIS' 400th episode. "Everything Starts Somewhere" is the second episode of the show's 18th season
The team conducts an unorthodox investigation when their suspects are trapped in a decompression chamber on NCIS. "Decompressed" is the 14th episode of the show's 13th season.
Ducky is attacked by somone who claims to have information about his deceased half-brother on NCIS. "Spinning Wheel" is the tenth episode of the show's 13th season.
Palmer: No. I don't want to. Ducky: You don't want to what, Mr. Palmer? Palmer: I don't want to know how much her liver weighs. I don't want to catalogue her scars. Most of all, I don't want to cut open another friend. Think I've had my limit.