NCIS: Los Angeles  has a mole, and their duplicity will compromise the lives and identities of the agency's undercover agents during "Between the Lines."

The White Ghost Returns To 'NCIS: LA' As Eric Enters The Field To Save Russian Missiles?

After a local gang tapes the execution of an unmasked undercover operative as a warning, Hetty (Linda Hunt) will task Sam (LL Cool J), Callen (Chris O'Donnell), and Deeks (Eric Christian Olsen) with tracking down the dangerous leak. Unfortunately, the mole may have spilled the beans on one of Sam's own aliases and the Navy SEAL may walk into a trap (see video below)

While Callen will literally go out on a ledge to solve the case (see gallery above), Granger (Miguel Ferrer) will begin to worry when Kensi (Daniela Ruah) drops off the grid. Her sudden realization that the White Ghost is her ex-fiancée Jack (Matthew Del Negro) and her inability to shoot him during "Fish Out of Water" may put her in even more danger than before.

The White Ghost's True Name Revealed By 'NCIS: LA' Actor

Written by Joseph C. Wilson ("Fallout," "Unwritten Rule") and helmed by long-time NCIS/NCIS: LA director Dennis Smith ("The Livelong Day," "Patriot Acts"), "Between the Lines" filmed in late January and Smith kindly dropped a few spoilers at that time.

"Fun #NCISLA ep first three days shooting. Sam rolls the dice and Callen rolls with Deeks. Kensi in the dark, humm?" Smith teased.

Find out more when "Between the Lines" airs on March 25 during NCIS: LA's usual 9 p.m. ET slot on CBS.