NCIS: Los Angeles Season 6 three-part finale starts with the airing of "Beacon" on April 20.

In the TV guide teaser for NCIS: Los Angeles season 6 episode 21 directed by Diana Valentine, Chris O'Donell's character Supervisory Special Agent G. Callen and LL COOL J's Senior Field Agent Sam Hanna unexpectedly meet up with an old friend whom they thought was murdered but has now surfaced to ask for help. The Special Projects team unearths a possible breach of America's economic sanctions against Russia.

In "Field of Fire", the second of the 3-part finale, Callen's team searches for a marine sniper who escapes a veterans hospital and turns up a connection to an extremist. As the naval team conducts their investigation, Daniela Ruah's character, Special Agent Kensi Blye is reminded of her job before joining NCIS.

Episode 22 is directed by Robert Florio ("Exposure," "Raven and the Swans") from a script written by Gil Grant ("Forest for the Trees", "Windfall").  

CBS Television Network has teased that based on these story lines, audiences may expect more twists and turns in the Episode 23 finale on May 18. NCIS: LA also stars Agent in Charge/Operations Manager Henrietta "Hetty" Lange (Linda Hunt), Assistant Director Owen Granger (Miguel Ferrer), LAPD Detective Marty Deeks (Eric Christian Olsen), Technical Operator Eric Beale (Barrett Foa), and Intelligence Analyst Nell Jones (Renée Felice Smith).

NCIS: Los Angeles is a television drama which premiered in September 2009. The LA division of NCIS apprehends dangerous and elusive criminals who pose a threat to national security. The Office of Special Projects team of Callen assumes false identities and uses the most advanced technology in their investigation.

The NCIS: Los Angeles Season 6 three-part finale airs on CBS Mondays at 10 p.m.