Set in 1991, NCIS: Origins finds a young Gibbs, portrayed by Austin Stowell, just starting out with the Naval Investigative Service (NIS) at Camp Pendleton. The stories depict Gibbs’ early experiences in the Navy and something that will change the course of his professional life in law enforcement. Mark Harmon, who aired as Gibbs in NCIS, narrates and is an executive producer of the series, which, of course, connects this prequel to the series. ​