See Harm & Mac's 'JAG' Reunion in the 'NCIS: LA' Finale Trailer (VIDEO)
[Warning: The below contains MAJOR spoilers for Season 10, Episode 23 of NCIS: Los Angeles, "The Guardian."]
"They haven't been in touch for some time," Elliott told TV Insider. "There's been some distance. But we work together again and interact and get along very much like we did back then."
The two are brought in to help the NCIS team track down a group of ISIS sympathizers. In "The Guardian," the investigation leads the agents to the USS Allegiance, the largest aircraft carrier in the U.S. fleet — and on which Harm is stationed. Soon after Sam (LL Cool J) and Callen (Chris O'Donnell) arrive on the ship, its agent afloat is found dead, meaning there's a killer on board.
But as Callen says in the trailer, the ship may not be the ISIS sympathizers' target. Instead, the team is likely looking at an espionage operation, which makes sense since they connect the dots to none other than Pavel Volkoff (David S. Lee) in Episode 23.
Volkoff may be dead now, but he was speaking with the victim's wife. They likely stumbled upon a Russian state-sanctioned operation. Furthermore, the victim was Russian, and his wife's office is cleared out when they get there.
That's going to be where Mac comes in in "False Flag," as Hetty (Linda Hunt) turns to her to help obtain information from a Russian diplomat.
NCIS: Los Angeles, Season 10 Finale, Sunday, 10/9c, CBS