We've seen glimpses of Leroy Jethro Gibbs before he was the Leroy Jethro Gibbs we came to know with Mark Harmon playing him for 19 seasons on NCIS , but now the franchise's newest series, NCIS: Origins , is delving deeper into that era. Austin Stowell is taking over the role (Harmon says), beginning with the two-hour premiere on Monday, October 14.

In "Enter Sandman," it's 1991, NCIS is NIS, and Gibbs is back from Desert Storm, grieving the deaths of his wife and daughter, and just beginning his career as a newly appointed special agent at the fledgling NCIS Camp Pendleton office. There, he's forging his place on a gritty team led by NCIS legend Mike Franks (Kyle Schmid). The cast also includes Mariel Molino as Special Agent Lala Dominguez, Tyla Abercrumbie as Field Operation Support Officer Mary Jo Sullivan, and Diany Rodriguez as Special Agent Vera Strickland. Check them and more out in the photos below.

"Mark Harmon has done a job that actors dream of. He's taken over the world and it's just a little daunting," Stowell told TV Insider as part of our extended fall preview of the new CBS drama. "But getting to know Mark has really been paramount for me to step into these shoes and try to fill them."

Executive producer Sean Harmon (who played the young Gibbs in flashbacks on NCIS and whose idea the series was) added, "I believe that very few people are truly 'born leaders' and instead are molded into them, and Gibbs is no exception. Delving into the backstory of 'the boss' seemed like a good opportunity to explore why Gibbs became the way he did and who was there to influence him along that journey."