The two-part episode sequence Ice Queen (2003) and Meltdown (2003), aired in the spring of 2003, was the back door pilot for NCIS (2003).
Alicia Coppola will go on to reprise her role as Cmdr. Faith Coleman on NCIS (2003). She will then play a different character, FBI Agent Lisa Rand on NCIS: Los Angeles (2009), which is part of the same universe as this series and NCIS.
Actress Zoe McLellan would go on to star in NCIS: New Orleans (2014), a spin-off NCIS (2003), which in itself originated as a spin-off of this series.
Agent Gibbs of the NCIS goes to the fictional USS Chattanooga in the Mediterranean Sea. There is no such ship in the US Navy. However, there have been two vessels by that name: a steam sloop, in service 1866-71, and C-16, a protected cruiser of the Denver class, in service 1904-21. There have been two proposals (in 1944 and -45) to give that name to two other ships, one of which was renamed Uniontown before its commissioning and the construction of the other was halted before completion. Although the establishing footage used for the scene shows a guided missile destroyer (USS Arleigh Burke, designated DDG-51), the letter designation of the Chattanooga is CG, not DDG, and therefore the Chattanooga, if real, would be a guided missile cruiser, most likely a Ticonderoga class based on the time period this is meant to have occurred.
Vyto Ruginis plays an agent here. He has also guest starred as Arkady Kolcheck on 25 episodes of NCIS: Los Angeles (2009), a spin off of NCIS (2003). This episode and the one prior serve as a backdoor pilot of NCIS (2003).