NCIS: ORIGINS follows a young Leroy Jethro Gibbs (Austin Stowell) in 1991, years prior to the events of NCIS, and is narrated by Mark Harmon. In the series, Gibbs starts his career as a newly minted special agent at the fledgling NCIS Camp Pendleton office, where he forges his place on a gritty ragtag team led by NCIS legend Mike Franks (Kyle Schmid).

NCIS: ORIGINS follows a young Leroy Jethro Gibbs (Austin Stowell) as he starts his career as a newly minted special agent at the fledgling NCIS Camp Pendleton office.

A murder near Camp Pendleton leads Gibbs and the team to a suburban mall in San Diego, where Gibbs takes matters into his own hands. Jackson Gibbs pays Franks an unexpected visit.

Still grieving the loss of his wife and daughter, Gibbs helps the team work a case involving a missing girl. The moment that irrevocably changed Gibbs' life is revealed.

With the countdown on to an execution, Franks races to extricate the location of a missing body from a death row inmate and honor a promise he made to the victim's sister before time runs out.

Gibbs goes undercover for the first time with Lala as NIS works the case of a dead Navy seaman who may have been sharing top-secret intel that poses a threat to national security.