Episode 18 of "NCIS: Los Angeles" titled "Fighting Shadows" will focus primarily on the relationship between Marty Deeks (Eric Christian Olsen) and Kensi Blye (Daniela Ruah) as they realize that, sooner or later, their co-workers would figure them out. 

TV Guide's official synopsis of the episode states that the primary case involves the team investigating an explosion that killed three FBI agents following what was reportedly a successful sting operation. Now the team has to find out who was the perpetrator behind the murder. 

The plot synopsis for "Fighting Shadows" also states that Operations Manager Hetty Lange is aware of Deeks and Kensi's relationship and separates them during the investigation. Deeks is paired with Callen (Chris O'Donnell) while Kensi spends the episode alongside Sam (LL Cool J). This gives the episode a fun edge as the show puts together investigative action with character drama. It also gives Ruah's and Olsen's characters a chance to spend more time interacting with the rest of the cast. 

There has also been speculation that the episode will reveal that Deeks is up to something.

Executive producer John Peter Kousakis stated in a recent tweet, "All I can say is... what has Deeks done? Even Hetty is in a quandary." 

Kousakis followed this with, "Who is tailing Kensi? It's a Deeks mystery. Does Hetty know?"

This statement indicates that whatever Deeks is up to, it may put Kensi's life in danger. It also brought up the discussion that this mystery might be the cause for Hetty separating the two during the investigation. 

"Fighting Shadows" will air on March 23, ending a short hiatus. The episode was directed by Tony Wharmby and penned by Andrew Bartels. This episode may also begin the main story arc of the next season as the series nears its season 6 finale (untitled episode due to air on May 11).