NCIS: Los Angeles 10x24 "False Flag" Season 10 Episode 24 Promo Trailer (Season Finale) - Callen and Sam work with Navy Captain Harmon “Harm” Rabb, Jr. (David James Elliott) to locate a group of ISIS sympathizers aboard the USS Allegiance. Also, Hetty enlists her friend, Navy Lieutenant Colonel Sarah “Mac” Mackenzie (Catherine Bell), to help obtain information from a Russian diplomat, on the 10th season finale of NCIS: LOS ANGELES, Sunday, May 19th on CBS.