• Actor LL Cool J plays NCIS Special Agent Sam Hanna in 'NCIS: LA'

Actor LL Cool J plays NCIS Special Agent Sam Hanna in 'NCIS: LA' (Photo : REUTERS/Mario Anzuoni)

"NCIS: Los Angeles" Season 6 finale airs Monday, May 18, on CBS. This season ender brings back Arkady, and the team heads over to Moscow in Russia to get to the bottom of the $100 million crude oil deal. Sam, Callen, Kensi and Deeks are seen in heavy gunfire in video promos for this season's last episode.

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Spoiler alert: This update contains mild "NCIS: Los Angeles" Season 6 finale spoilers. Read on at your own risk.

In a promo video off the "NCIS: Los Angeles" Season 6 finale, Sam (LL Cool J) finds Anna Kolcheck (Bar Paly), but she does not cooperate. She fails to notice Callen (Chris O'Donnell) closing in. She loses control but calms down when she realizes Sam and Callen may have really been working with Arkady Kolcheck (Vyto Ruginis).

The "NCIS: Los Angeles" Season 6 finale is titled, "Chernoff, K." In a separate promo video, Sam, Callen, Kensi (Daniela Ruah) and Deeks (Eric Christian Olsen) figure in combat against heavily armed masked men. This teaser scene is action-packed, intense and compelling.

"[NCIS: Los Angeles] Season 6 ends with the team traveling to Moscow where they assume multiple undercover identities to locate suspects in an ongoing case. Meanwhile, Callen uncovers new information regarding his father," reads the episode synopsis on TV.com.

In another promo video, Callen is seen making thinly veiled threats to get real information about his father. Will Arkady finally tell Callen everything he knows about his roots?

"NCIS: Los Angeles" 6x24 was written by Kyle Harimoto and directed by John Peter Kousakis.

WATCH: 'NCIS: Los Angeles' Season 6 Finale Video Promo (CBS On YouTube)