“Iceman” first aired March 20, 2007.

“Iceman” welcomes back one of the show’s most compelling characters, Former NCIS Special Agent Mike Franks (Muse Watson), the man who trained Special Agent Leroy Jethro Gibbs (Mark Harmon) upon the latter’s release from his Marine Corps commission. His brief return develops his character better than any single character this season.

“Iceman” opens with NCIS Medical Examiner Dr. Donald "Ducky" Mallard (David McCallum) entering his domain of the NCIS morgue for an early morning autopsy of one Marine Corporal Liam O'Neill (Jeremy Roberts) who was found ostensibly frozen to death the previous day. Ducky opens the body bag to find a fit Caucasian man in his early twenties who apparently sustained some trauma to his face. About the time Ducky notes this fact, Corporal O'Neill opens his eyes and inhales deeply. Ever the Scot, Ducky takes it all in stride and the episode is off.

Opening headquarters banter between Special Agents Tim McGee (Sean Murray), Tony DiNozzo (Michael Weatherly), and Mossad Agent-on-Loan-to-NCIS Ziva David (Cote de Pablo) addresses Ziva’s uncharacteristic tardiness, DiNozzo’s serial tardiness, and alludes to both Christ’s raising of Lazarus and past episode ”Dead Man Walking" all in one dialog. DiNozzo reveals that Corporal O'Neill was to be redeployed to Baghdad in two days after 15 days stateside.

In the morgue, Ducky and Gibbs discuss the case, Ducky dithering on, trying Gibbs' poor patience. Just when Gibbs thinks Ducky has nothing to offer him, the doctor informs Gibbs that the Corporal was struck in the head and his face held in the snow until the Corporal was “dead.” Ducky defined the prognosis as equivocal. Out at the crime scene DiNozzo is on the phone with Dr. Jeanne Benoit (Scottie Thompson), whispering sweet nothings while Ziva declares to McGee that DiNozzo has commitment issues (the lady protests too much, methinks). DiNozzo’s side of the conversation is a bit cheap as he and Benoit make plans while Ziva finds the Corporal’s cell phone. The team locates the Corporal’s car and searches it.

Gibbs and Abby have a summit at the lab where Abby alerts Gibbs to a packet of some green organic substance yet to be identified and some receipts indicating that the Corporal had spent some time back in Baghdad during his two-week furlough in the States. McGee identifies the Corporal’s trip within his trip. Apparently, O'Neill left the US eight days previously under his civilian identification, arriving back two days ago. His transportation was on a cargo transport called Fast Flight (presumably making his detection as an airline passenger impossible through standard channels).

Gibbs and Ziva go to check out Fast Flight and meet one Nick Taylor (Steven Elder), owner of the operation. When confronted with O'Neill's transport, Taylor proved all was legal and that the flight was free for the Marine. Taylor explained that he understood that O'Neill was returning because his unit had been hit and his friends injured. When Ziva revealed that someone attempted to kill O'Neill, Taylor was taken aback and revealed that O'Neill met some “BAGs” (bad-ass guys) in Baghdad. Ziva receives a call alerting her that someone is at the hospital. Gibbs assumes next of kin; Ziva replies O'Neill has no next of kin and the pair arrive back at the hospital to find Former NCIS Special Agent Mike Franks at his son’s bedside.