‘NCIS’ Episode 400: Gibbs & Ducky Meet in Flashbacks (PHOTOS)

NCIS has reached another milestone — its 400th episode! — and the November 24 episode is going way back in the history of two of its original characters: Special Agent Leroy Jethro Gibbs (Mark Harmon) and former medical examiner, current historian Dr. Donald “Ducky” Mallard (David McCallum).

In “Everything Starts Somewhere,” flashbacks will show the murder case that introduced a young Gibbs (played by Sean Harmon, Mark’s son) to NCIS, then NIS (he won’t join for some time) and young, new-to-America Ducky (played by Adam Campbell).

Both characters “are at crossroads in their lives,” executive producer Frank Cardea previously told TV Insider. “They [will] help each other find their life paths.”

Scroll down for a look at Gibbs and Ducky, both past and present, in Episode 400.

NCIS, Tuesdays, 8/7c, CBS